Comparing DNA Results – Different Tests at the Same Testing Company

Several people have asked about different tests at the same DNA testing company. They wondered if matching is affected, meaning whether your matches are different if you have two different tests at the same company. Specifically, they asked if you are better off purchasing a test AT a DNA testing vendor that allows uploads, rather than uploading a test from a different vendor. Does it make a difference to the tester or their matches? Do they have the same matches?

These are great questions, and the answer isn’t conclusive. It varies based on several factors.

Having multiple tests at the same DNA testing company can occur in three ways:

  • The same person tests twice at the same DNA testing company.
  • The same person tests once at the DNA testing company and uploads a test from a different testing company. Only two of the primary four DNA testing companies accept uploads from other vendors – FamilyTreeDNA and MyHeritage.
  • The same person uploads two different files from other DNA testing companies to the DNA testing company in question. For example, the DNA company could be FamilyTreeDNA and the two uploaded DNA files could be from either MyHeritage, 23andMe or Ancestry.

All DNA testing companies allow users to download their raw DNA data files. This enables the tester to upload their DNA file to the vendors who accept uploaded files. Both FamilyTreeDNA and MyHeritage provide matching for free, but advanced tools require a small unlock fee of $19 and $29, respectively.

Testing Company Accepts Uploads from Other Companies Download Upload Instructions
23andMe No Instructions here
Ancestry No Instructions here
FamilyTreeDNA Yes, some Instructions here
MyHeritage Yes, some Instructions here

I wrote about developing a DNA testing and transfer/upload strategy, here, and about which companies accept which tests, here.

Not all DNA files are created equal. Therefore, not all files from vendors are compatible with other vendors for various reasons.

Multiple Tests at the Same DNA Testing Company

I have at least two tests at each of the four major vendors. I did this for research purposes, meaning to write articles to share with you.

If you actually test twice at a vendor, meaning purchase two separate tests and take them yourself, you will have two test results at that testing company. At some companies, specifically 23andMe, if you purchase a new test through their “upgrade” procedure, you won’t have two tests, just the newer one.

However, if you’re testing at the DNA testing company, and also uploading, I generally don’t recommend more than one test at each vendor. All it really does is clog up people’s match lists with no or little additional benefit. At 23andMe, with their restrictions on the size of your match list, if everyone had two tests, the effective match limit would be half of their stated limit of about 1500 matches for earlier testers and about 5000 for current testers with subscriptions.

So, in essence, I’m telling you to “do as I say, not as I do.” We all have better things to do with our money rather pay for the same test twice. If you haven’t tested your Y-DNA or mitochondrial DNA, that’s much more beneficial than two autosomal tests at one vendor.

Chips and Chip Evolution

Before we begin the side-by-side comparison, let’s briefly discuss DNA testing chips and how they work.

Each DNA testing company purchases DNA processing equipment. Illumina is the big dog in this arena. Illumina defines the capacity and structure of each chip. In part, how the testing companies use that capacity, or space on each chip, is up to each company. This means that the different testing companies test many of the same autosomal DNA SNP locations, but not all of the same locations.

Furthermore, the individual testing companies can specify a number of “other” locations to be included on their chip, up to the chip maximum size limit. The testing companies who offer Y-DNA or mitochondrial DNA haplogroups from autosomal tests use part of their chip array space for selected known haplogroup-defining SNP locations. This does NOT mean that Y-DNA or mitochondrial DNA is autosomal, just that the testing company used part of their chip array space to target these SNPs in your genome. Of course, for your most refined haplogroup and Y-DNA or mitochondrial DNA matching, you have to take those specific tests at FamilyTreeDNA .

This means that each testing company includes and reports many of the same, but also some different SNP locations when they scan your DNA.

In the lab, after your DNA is extracted from either your saliva or the cheek swab, it’s placed on this array chip which is then placed in the processing equipment.

There are several steps in processing your DNA. Each DNA location specified on the chip is scanned and read multiple times, and the results are recorded. The final output is the raw DNA results file that you see if/when you download your raw DNA file.

Here’s an example from my file. The RSID is the reference SNP cluster ID which is the naming convention used for specific SNPs. It’s not relevant to you, but it is to the lab, along with the chromosome number and position, which is in essence the address on the chromosome.

In the Result column, your file reports one nucleotide (T, A, C or G) that you inherited from each parent at each tested position. They are not listed in “parent order” because your DNA is not organized in that fashion. There’s no way for the lab to know which nucleotide came from which parent, unless they are the same, of course. You can read about nucleotides, here.

When you upload your raw DNA file to a different DNA testing company (vendor), they have to work with a file that isn’t entirely compatible with the files they generate, or the other files uploaded from other DNA testing companies.

In addition to dealing with different file formats and contents from multiple DNA vendors, companies change their own chips and file structure from time to time. In some cases, it’s a forced change by the chip manufacturer. Other times, the vendors want to include different locations or make improvements. For example, with 23andMe’s focus on health, they probably add new medically related SNP locations regularly. Regardless of why, some DNA files include locations not included in other files and are not 100% compatible.

Looking at the first few entries in my example file above, let’s say that the testing vendor included the first ten positions, but an uploaded file from another company did not. Or perhaps the chip changed, and a different version of the company’s own file contains different positions.

DNA testing companies have to “fill in the blanks” for compatibility, and they do this using a technique called imputation. Illumina forced their customers to adopt imputation in 2017 when they dropped the capacity of their chip. I was initially quite skeptical, but imputation has worked surprisingly well. Some of the matching differences you will see when comparing the results of two different DNA files is a result of imputation.

I wrote about imputation in an early article here. Please note the companies have fixed many issues with imputation and improved matching greatly, but the concepts and imputation processes still apply. The downloaded raw data files are your results BEFORE imputation, meaning that it’s up to any company where you upload to process your raw file in the same way they would process a file that they generated. A lot goes on behind the scenes when you upload a file to a DNA testing company.

At both 23andMe and Ancestry, you know that all of your matches tested there, meaning they did not upload a file from another testing company. You don’t know and can’t tell what chip was utilized when your matches tested. The only way to determine a chip testing version, aside from knowing the date or remembering the chip version from when you tested, is to look at the beginning of the raw data download file, although not all files contain that information.

Ok, now that you understand the landscape, let’s look at my results at each company.

23andMe

I tested twice at 23andMe on two different chip versions, V3 and V4, which tested some different locations of my DNA. Neither of these chips is the current version. I originally tested twice to evaluate the differences between the two test versions which you can read about, here.

23andMe named their ethnicity results Ancestry Composition.

They last updated my V3 test’s Ancestry Composition results on July 28, 2021.

The percentages are shown at left, and the country locations are highlighted at right for my 23andMe V3 test.

Click to enlarge any graphic

The 23andMe V4 test was also updated for the last time on July 28, 2021.

The ethnicity results differ substantially between the two chip versions, even though they were both updated on the same date.

In October of 2020, in an effort to “encourage” their customers to pay for a new test on their V5 chip, 23andMe announced that there would be no ethnicity updates on older tests. So, I really don’t know for sure when my tests were actually updated. Just note how different the results are. It’s also worth mentioning that 23andMe does not show trace amounts on their map, so even though my Indigenous American results were found, they aren’t displayed on the map.

Indigenous is, however, shown in yellow on their DNA Chromosome Painting.

No other testing company restricts updates, penalizing their customers who purchased earlier versions of tests.

Matches at 23andMe

23andMe limits your matches to about 1500 unless you have purchased the current test, including health AND pay for an annual $69 subscription which buys you about 5000 matches. I have not purchased this test.

Your number of actual matches displayed/retained is also affected by how many people you have communicated with, or at least initiated communications with. 23andMe does not roll those people off of your match list.

I have 1803 matches on both of my tests, meaning I’ve reached out to about 300 people who would have otherwise been removed from my match list. 23andMe retains your highest matches, deleting lower matches after you reach the maximum match threshold.

I’ve randomly evaluated several of the same matches at each vendor, at least five maternal and five paternal, separated by a blank row. I wanted to determine whether they match me on the same number of centimorgans, meaning the same amount of DNA, on both tests, and the same number of segments.

Match 23and Me V3 23and Me V4
Patricia 292 cM – 12 segments Same as V3
Joe 148 cM, 8 segments Same
Emily 73 cM, 4 segs 72 cM, 4 seg
Roland 27 cM, 1 seg Same
Ian 62 cM, 4 seg Same
Stacy 469 cM, 16 segments 482 cM, 16 segments
Harold 134 cM, 6 segments Same
Dean 69 cM, 3 seg Same
Carl 95 cM, 4 seg Same
Debbie 83 cM, 4 seg 84 cM, 4 seg

As you can see, the matches are either exact or xclose.

Please note that bolded matches are also found at another company. I will include a summary table at the end comparing the same match across multiple vendors.

23and Me Summary

The 23andMe V3 and V4 match results are very close. Since the match limit is the same, and the results are so close between tests, they are essentially identical in terms of matching.

The ethnicity results are similar, but the V4 test reflects a broader region. Italian baffles me in both versions.

Ethnicity should never be taken at face value at any DNA testing company, especially with smaller percentages which could be noise or a combination of other regions which just happens to resemble Italy, in my case.

I don’t know what type of comparison the current chip would yield since I suspect it has more medical and less genealogical SNPs on board.

Reprocessing Tests

This is probably a good place to note that it’s very expensive for any company to update their customer’s ethnicity results because every single customer’s DNA results file must be completely rerun. Note that this does not mean their DNA itself is retested. The output raw data file is reprocessed using a new algorithm.

Rerunning means reprocessing that specific portion of every test, meaning the vendors must rent “time in the cloud.” We are talking millions of dollars for each run. I don’t know how much it costs per test, but think about the expense if it takes $1 to rerun each test in the vendor’s database. Ancestry has more than 20 million tests.

While we, as consumers, are always chomping at the bit for new and better ethnicity results – the testing companies need to be sure it really is “better,” not just different before they invest the money to reprocess and update results.

This is probably why 23andMe decided to cease updating older kits. The newer tests require a subscription which is recurring revenue.

The same is true when DNA testing companies need to rematch their entire user base. This happens when the criteria for matching changes. For example, Ancestry purged a large number of matches for all of their customers back in 2020. While match algorithm changes necessitate rematching, with associated costs, this change also provided Ancestry with the huge benefit of eliminating approximately half of their customer’s matches. This freed up storage space, either physically in their data center or space rented in the cloud, representing substantial cost-savings.

How long can a DNA testing company reasonably be expected to continue investing in a product which never generates additional revenue but for which the maintenance and reinvestment costs never end?

Ancestry and MyHeritage both hope to offset the expenses of maintaining their customer’s DNA tests and providing free updates by selling subscriptions to their record services. 23andMe wants you to purchase a new test and a yearly subscription. FamilyTreeDNA wants you to purchase a Big Y-DNA and mitochondrial DNA test.

OK, now let’s look at my matches at Ancestry.

Ancestry

I’ve taken two Ancestry tests, V1 and V2. There were some differences, which I wrote about here and here. V2 is no longer the current chip.

Except for 23andMe who wants their customers to purchase their most current test, the other companies no longer routinely announce new chip versions. They just go about their business. The only way you know that a vendor actually changed something is when the other companies who accept uploads suddenly encounter an issue with file formats. It always takes a few weeks to sort that out.

My Ancestry V1 test’s ethnicity results don’t show my Native American ethnicity.

Ancestry results were updated in June 2022

However, my V2 results do include Native American ethnicity.

Matches at Ancestry

I have many more matches on my V1 test at Ancestry because I took steps to preserve my smaller matches when Ancestry initiated its massive purge in 2020. I wrote about that here and here.

Ancestry’s SideView breaks matches down into maternal, paternal, and unassigned based on your side selection. You tell Ancestry which side is which. You may be able to determine which “side” is maternal or paternal either by your ethnicity or shared matches. While SideView is not always accurate, it’s a good place to begin.

Match Category Ancestry V1 Test Ancestry V2 Test
Maternal 15,587 15,116
Paternal 42,247 41,870
Both 2 2
Unassigned 48,999 4,127
Total 106,835 61,115

Ancestry either displays all your matches or your matches by side, which I used to compile the table above. I suspect that Ancestry is not assigning any of the smaller preserved matches to “sides” based on the numbers above.

Ancestry implemented a process called Timber that removes DNA that they feel is “too matchy,” meaning you match enough people in this region that they think it’s a pileup region for you personally, and therefore not useful. In some cases, enough DNA is removed causing that person to no longer be considered a match because they fall beneath the match threshold. I am not a fan of Timber.

Your match amount shown is AFTER Timber has removed those segments. Unweighted shared DNA is your pre-Timber match amount.

You can view the Unweighted shared DNA by clicking on the amount of shared DNA on your match list.

You can read Ancestry’s Matching White Paper, here.

Let’s take a look at my matches. I’ve listed both weighted and unweighted where they are different.

Match Ancestry V1 Ancestry V2
Michael 755 cM, 35 seg 737 cM, 33 seg
Edward 66 cM, 4 seg (unweighted 86 cM) 65 cM, 4 seg (unweighted 86 cM)
Tom 59 cM, 3 seg (unweighted 63) Same
Jonathon 43 cM, 4 seg, (unweighted 52 cM) Same
Matthew 20 cM, 2 seg (unweighted 35 cM) Same
Harold 132 cM, 7 seg 135 cM, 6 seg
Dean 67 cM, 4 seg (unweighted 78 cM) 66 cM, 4 seg (unweighted 78 cM)
Debbie 93 cM, 5 seg Same
Valli 142 cM, 3 seg Same
Jared 20 cM, 1 seg (unweighted 22 cM) Same

Timber only removes DNA when the match is under 90 cM. Almost every match under 90 cM has some DNA removed.

Ancestry Summary

The results of the two Ancestry tests are very close.

In some circumstances, no DNA is removed by Timber, so the unweighted is the same as the weighted. However, in other cases, a significant amount is removed. 15 cM of Matthew’s 35 cM was removed by Timber, reducing his total to 20 cM.

Remember that Ancestry does not show shared matches unless they are greater than 20 cM, which is different than any other DNA testing company.

At one point, Ancestry was selling a health test that was also a genealogy test. That test utilized a different chip that is not accepted for uploads by other vendors. The results of that test might well be different that the “normal” Ancestry tests focused on genealogy. The Ancestry health test is no longer offered.

Companies that Accept Uploads

DNA testing companies that accept uploaded DNA files from other DNA testing companies need to process the uploaded file, just like a file that is generated in their own lab. Of course, they must deal with the differences between uploaded files and their own file format. The processing includes imputation and formulates the uploaded file so that it works with the tools that they provide for their customers, including ethnicity (by whatever name they use) matching, family matching (bucketing), advanced matching, the match matrix, triangulation, AutoClusters, Theories of Family Relativity, and other advanced tools.

Of course, the testing company accepting uploads can only work with the DNA locations provided by the original DNA testing company in the uploaded file.

Matching and some additional tools are free to uploaders, but advanced tools require an inexpensive unlock.

FamilyTreeDNA

I took a test at FamilyTreeDNA, plus uploaded a copy of both of my Ancestry DNA files.

FamilyTreeDNA named their population (ethnicity) test myOrigins and the current version is V3. I wrote about the rollout and comparison in September of 2020, here.

My DNA test taken at FamilyTreeDNA, above, reveals Native American segments that match reference populations found both in North and South America and the Caribbean Islands.

At FamilyTreeDNA, my Ancestry V1 uploaded file results show Native American population matches only in North America.

Interestingly, my Ancestry V1 file processed AT Ancestry did not reveal Native American ancestry, but the same file uploaded to and processed at FamilyTreeDNA did show Native American results, reflecting the difference between the vendors’ internal algorithms and reference populations utilized.

My myOrigins results from my Ancestry V2 uploaded file at FamilyTreeDNA also include my North American Native American segments. The V2 test also showed Native American ethnicity at Ancestry, so clearly something changed in Ancestry’s algorithm, locations tested, and/or reference populations between V1 and V2.

Fortunately, FamilyTreeDNA provides both chromosome painting and a population download file so I can match those Native segments with my autosomal matches to identify which of my ancestors contributed those specific segments.

One of my Native segments is shown in pink on Chromosome1. My mother has a Native segment in exactly the same location, so I know that this segment originated with my mother’s ancestors.

I downloaded the myOrigins population segment file and painted my results at DNAPainter, along with the matches where I can identify our common ancestor. This allowed me to pinpoint the ancestral line that contributed this Native segment in my maternal line. You can read about using DNAPainter, here.

FamilyTreeDNA Matches

I have significantly more matches at FamilyTreeDNA on their test than on either of my Ancestry tests that I uploaded. However, nearly the same number are maternally or paternally assigned through Family Matching, with the remainder unassigned. You can read about Family Matching here.

Match Category FamilyTreeDNA Test Ancestry V1 at FamilyTreeDNA Ancestry V2 at FamilyTreeDNA
Paternal 3,479 3,572 3,422
Maternal 1,549 1,536 1,477
Both 3 3 3
All 8,154 6,397 6,579

Family matching, aka bucketing, automatically assigns my matches as maternal and paternal by linking known relatives to their place in my tree.

I completed the following match chart using my original test taken at FamilyTreeDNA, plus the same match at FamilyTreeDNA for both of my Ancestry tests.

In other words, Cheryl matched me at 467 cM on 21 segments on the original test taken at FamilyTreeDNA. She matched me on 473 cM and 21 segments on my Ancestry V1 test uploaded to FamilyTreeDNA and on 483 cM and 22 segments on the Ancestry V2 test uploaded to FamilyTreeDNA.

Match FamilyTreeDNA Ancestry V1 at FTDNA Ancestry V2 at FTDNA
Cheryl 467 cM, 21 seg 473 cM, 21 seg 483 cM, 22 seg
Patricia 195 cM, 11 seg 189 cM, 11 seg 188 cM, 11 seg
Tom 77 cM, 4 seg 71 cM, 4 seg 76 cM, 4 seg
Thomas 72 cM, 3 seg 71 cM, 3 seg 74 cM, 3 seg
Roland 29 cM, 1 seg 35 cM, 2 seg 35 cM, 2 seg
Rex 62 cM, 4 seg 55 cM, 3 seg 57 cM, 3 seg
Don 395 cM, 18 seg 362 cM, 15 seg 398 cM, 18 seg
Ian 64 cM, 4 seg 56 cM, 4 seg 64 cM, 4 seg
Stacy 490 cM, 18 seg 494 cM, 15 seg 489 cM, 14 seg
Harold 127 cM, 5 cM 133 cM, 6 seg 143 cM, 6 seg
Dean 81 cM, 4 seg 75 cM, 3 seg 83 cM, 4 seg
Carl 103 cM, 4 seg 101 cM, 4 seg 102 cM, 4 seg
Debbie 99 cM, 5 seg 97 cM, 5 seg 99 cM, 5 seg
David 373 cM, 16 seg 435 cM, 19 seg 417 cM, 18 seg
Amos 176 cM, 7 seg 177 cM. 8 seg 177 cM, 7 seg
Buster 387 cM, 15 seg 396 cM, 16 seg 402 cM, 17 seg
Charlene 461 cM, 21 seg 450 cM, 21 seg 448 cM, 20 seg
Carol 65 cM, 6 seg 64 cM, 6 seg 65 cM, 6 seg

I have tested many of my cousins at FamilyTreeDNA and encouraged others to test or upload. I’ve attempted to include enough people so that I can have common matches at least at one other DNA testing company for comparison.

FamilyTreeDNA Summary

The matches are relatively close, with a few being exact.

Interestingly, some of the segment counts are different. In most cases, this results from one segment being broken into multiple segments by one or more of the tests, but not always. In the couple that I checked, the entire segment seems to descend from the same ancestral couple, so the break is likely a result of not all of the same DNA locations being tested, plus the limits of imputation.

MyHeritage

I have two tests at MyHeritage. One taken at MyHeritage, and an uploaded file from FamilyTreeDNA.

MyHeritage displays both ethnicity results and Genetic Groups which maps groups of people that you match. I left the Genetic Groups setting at the highest confidence level. Shifting it to lower displays additional Genetic Groups, some of which overlap with or are within ethnicity regions.

My test taken at MyHeritage, above, shows several ethnicities and Genetic Groups, but no Native American.

My FamilyTreeDNA kit processed at MyHeritage shows the same ethnicity regions, one additional Genetic Group, plus Native American heritage in the Amazon which is rather surprising given that I don’t show Native in North American regions where I’m positive my Native ancestors lived.

MyHeritage Matching

At MyHeritage, I compared the results of the test I took with MyHeritage, and a test I uploaded from FamilyTreeDNA. Fewer than half of my matches can be assigned to a parent via shared matching.

Matches MyHeritage Test FamilyTreeDNA at MyHeritage
Paternal 4,422 6,501
Maternal 2,660 3,655
Total 13,233 16,147

I have rounded my matches at MyHeritage to the closest cM.

Match MyHeritage Test FamilyTreeDNA at MyHeritage
Michael 801 cM, 32 seg 823 cM, 31 segments
Cheryl 467 cM, 23 seg 477 cM, 23 seg
Roland No match 28 cM, 1 seg
Patty 156 cM, 9 seg 151 cM, 9 seg
Rex 43 cM, 4 seg 53 cM, 3 seg
Don 369 cM, 16 seg 382 cM, 17 seg
 
David 449 cM, 17 seg 460 cM, 17 seg
Charlene 454 cM, 23 seg 477 cM, 24 seg
Buster 408 cM, 15 seg 410 cM, 16 seg
Amos 183 cM, 8 seg Same
Carol 78 cM, 6 seg 87 cM, 7 seg

MyHeritage Summary

I was surprised to discover that Roland had no match with the MyHeritage test, but did with the FamilyTreeDNA test. I wonder if this is a searching or matching glitch, especially since both companies use the same chip. 28 cM in one segment is a reasonably large match, and even if it was divided in two, it would still be over the matching threshold. I know this is a valid match because Roland triangulates with me and several cousins, I’m positive of our common ancestor, and he also matches me at both FamilyTreeDNA and 23andMe.

Other than that, the matches are reasonably close, with one being exact.

Your Matches Aren’t Everyplace

I unsuccessfully searched for someone who was a match to me in all four databases. Ancestry does not permit match downloads, so I had to search manually. People don’t always use the same names in different databases.

Surprisingly, I was unable to find one match who is in all of the databases. Many people only suggest testing at Ancestry because they have the largest database, but if you look at the following comparison chart that I’ve created, you’ll see that 16 of 26 people, or 62% were not at Ancestry. Conversely, many people were at Ancestry and not elsewhere. I could not find five maternal and five paternal matches at Ancestry that I could identify as matches in another database. 40% were not elsewhere.

If you think for one minute that it doesn’t matter for genealogy if you’re in all four major databases, please reconsider. It surely does matter.

Every single vendor has matches that the others don’t. Substantial, important matches. I have found first and second-cousin matches in every database that weren’t elsewhere.

Many of the original testers have passed away and can’t test again. My mother can never test at either 23andMe or Ancestry, but she is at both FamilyTreeDNA and MyHeritage because I could upgrade her kit at FamilyTreeDNA after she died. I uploaded her to MyHeritage. Of course, because she is a generation closer to our ancestors, she has many valuable matches that I don’t.

Each vendor provides either an email address or a messaging platform for you to contact your matches. Don’t be discouraged if they don’t answer. Just today, I received a reply that was years in the making.

Genealogists hope for immediate gratification, but we are actually in this for the long game. Play it with every tool at your disposal.

The Answer

Does it matter if you test at a DNA testing company, or upload a file?

I know this was a very long answer to what my readers hoped was a simple yes or no question.

There is no consistent answer at either FamilyTreeDNA or MyHeritage, the two DNA testing companies that accept uploads. Be sure you’re in both databases. My closest two matches that I did not test were found at MyHeritage. Here’s a direct link to upload at MyHeritage.

Of the vendors, those two should be the closest to each other because they are both processed in the GenebyGene lab, but again, the actual chip version, when the test was originally taken, and each vendor’s internal processing will result in differences. Neither the original test at the DNA testing company nor the uploaded files have consistently higher or lower matches. Neither type of test or upload appears to be universally more or less accurate. Differences in either direction seem to occur on a match-by-match basis. Many are so close as to be virtually equivalent, with a few seemingly random exceptions. Of course, we always have to consider Timber.

If you upload, unlock the advanced features at both FamilyTreeDNA and MyHeritage.

If you upload to a DNA testing company, you may discover in the future that some features and functions will only be available to original testers.

Personally, if I had the option, I would test at the company directly simply because it eliminates or at least reduces the possibility of future incompatibilities – with the exception of 23andMe which has chosen to not provide consistent updates to older tests. I’m incredibly grateful I didn’t test my mother or now deceased family members at 23andMe, and only there. I would be heartsick, heartbroken, and furious.

Our DNA is an extremely valuable resource for our genealogy. It’s the gift that truly keeps on giving, day after day, even when other records don’t exist. Be sure you and your family members are in each database one way or another, and test your Y-DNA (for males) and mitochondrial DNA (for everyone) to have a complete arsenal at your disposal.

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What Is a Sibling Anyway? Full, Half, Three-Quarters, Step, Adopted, Donor-Conceived & Twins

I’ve seen the term sibling used many different ways, sometimes incorrectly.

When referring to their own siblings, people usually use the term brother or sister, regardless of whether they are talking about a full, half or step-sibling. It’s a term of heart or description. It’s often genealogists who are focused on which type of sibling. As far as I’m concerned, my brother is my brother, regardless of which type of brother. But in terms of genetics, and genealogy, there’s a huge difference. How we feel about our sibling(s) and how we are biologically related are two different things.

Let’s cover the various types of siblingship and how to determine which type is which.

  • Full Siblings – Share both parents
  • Half-Siblings – Share only one parent
  • Three-Quarter Siblings – It’s complicated
  • Adopted Siblings
  • Donor-Conceived
  • Step-Siblings – Share no biological parent
  • Twins – Fraternal and Identical

Full Siblings

Full siblings share both parents and share approximately 50% of their DNA with each other.

You can tell if you are full siblings with a match in various ways.

  1. You share the same fairly close matches on both parents’ sides. For example, aunts or uncles or their descendants.

Why do I say close matches? You could share one parent and another more distant relative on the other parent’s side. Matching with close relatives like aunts, uncles or first cousins at the appropriate level is an excellent indicator unless your parents or grandparents are available for testing. If you are comparing to grandparents, be sure to confirm matches to BOTH grandparents on each side.

  1. Full siblings will share in the ballpark of 2600 cM, according to DNAPainter’s Shared cM Tool.

Keep in mind that you can share more or less DNA, hence the range. It’s also worth noting that some people who reported themselves as full siblings in the Shared cM project were probably half siblings and didn’t realize it.

  1. Full siblings will share a significant amount of fully identical regions (FIR) of DNA with each other, meaning they share DNA at the same DNA address from both parents, as illustrated above. Shared DNA with each other inherited from Mom and Dad are blocked in green. The fully identical regions, shared with both parents, are bracketed in purple. You can’t make this determination at FamilyTreeDNA, MyHeritage or Ancestry, but you can at both 23andMe and GEDmatch.

At GEDmatch, the large fully green areas in the chromosome browser “graphics and positions” display indicates full siblings, where DNA is shared from both parents at that location.

I wrote about the details of how to view fully identical regions (FIR) versus half identical regions (HIR) in the article, DNA: In Search of…Full and Half-Siblings.

  1. If your parents/grandparents have tested, you and your full sibling will both match both parents/grandparents. Yes, I know this sounds intuitive, but sometimes it’s easy to miss the obvious.

At FamilyTreeDNA, you can use the matrix tool to see who matches each other in a group of people that you can select. In this case, both siblings are compared to the father, but if the father isn’t available, a close paternal relative could substitute. Remember that all people who are 2nd cousins or closer will match.

  1. At Ancestry, full siblings will be identified as either “brother” or “sister,” while half-siblings do not indicate siblingship. Half-siblings are called “close family” and a range of possible relationships is given. Yes, Ancestry, is looking under the hood at FIR/HIR regions. I have never seen a full sibling misidentified as anything else at Ancestry. Unfortunately, Ancestry does not give customers access to their matching chromosome segment location data.
  2. Y-DNA of males who are full siblings will match but may have some slight differences. Y-DNA alone cannot prove a specific relationship, with very rare exceptions, but can easily disprove a relationship if two males do not match. Y-DNA should be used in conjunction with autosomal DNA for specific relationship prediction when Y-DNA matches.
  3. Y-DNA testing is available only through FamilyTreeDNA, but high-level haplogroup-only estimates are available through 23andMe. Widely divergent haplogroups, such as E versus R, can be considered a confirmed non-match. Different haplogroups within the same base haplogroup, such as R, but obtained from different vendors or different testing levels may still be a match if they test at the Big Y-700 level at FamilyTreeDNA.
  4. Mitochondrial DNA, inherited matrilineally from the mother, will match for full siblings (barring unusual mutations such as heteroplasmies) but cannot be used in relationship verification other than to confirm nonmatches. For both Y-DNA and mitochondrial DNA, it’s possible to have a lineage match that is not the result of a direct parental relationship.
  5. Mitochondrial DNA testing is available only through FamilyTreeDNA, but haplogroup-only estimates are included at 23andMe. Different base haplogroups such as H and J can be considered a non-match.
  6. A difference in ethnicity is NOT a reliable indicator of half versus full siblings.

Half-Siblings

Half-siblings share only one parent, but not both, and usually share about 25% of their DNA with each other.

You will share as much DNA with a half-sibling as you do some other close matches, so it’s not always possible for DNA testing companies to determine the exact relationship.

Referencing the MyHeritage cM Explainer tool, you can see that people who share 1700 cM of DNA could be related in several ways. I wrote about using the cM Explainer tool here.

Hints that you are only half-siblings include:

  1. At testing vendors, including Ancestry, a half-sibling will not be identified as a sibling but as another type of close match.
  2. If your parents or grandparents have tested, you will only match one parent or one set of grandparents or their descendants.
  3. You will not have shared matches on one parent’s side. If you know that specific, close relatives have tested on one parent’s side, and you don’t match them, but your other family members do, that’s a very big hint. Please note that you need more than one reference point, because it’s always possible that the other person has an unknown parentage situation.
  4. At 23andMe, you will not show fully identical regions (FIR).
  5. At GEDmatch, you will show only very minimal FIR.

Scattered, very small green FIR locations are normal based on random recombination. Long runs of green indicate that significant amounts of DNA was inherited from both parents. The example above is from half-siblings.

  1. At FamilyTreeDNA and 23andMe, most men who share a mother will also share an X chromosome match since men only inherit their X chromosome from their mother. However, it is possible for the mother to give one son her entire X chromosome from her father, and give the other son her entire X chromosome from her mother. Therefore, two men who do share a mother but don’t have an X chromosome match could still be siblings. The X is not an entirely reliable relationship predictor. However, if two men share an entire X chromosome match, it’s very likely that they are siblings on their mother’s side, or that their mothers are very close relatives.

Three-Quarter Siblings

This gets a little more complicated.

Three-quarter siblings occur when one parent is the same, and the other parents are siblings to each other.

Let’s use a real-life example.

A couple marries and has children. The mother dies, and the father marries the mother’s sister and has additional children. Those children are actually less than full siblings, but more than half-siblings.

Conversely, a woman has children by two brothers and those children are three-quarter siblings.

These were common situations in earlier times when a man needed a female companion to raise children and women needed a male companion to work on the farm. Neither one could perform both childcare and the chores necessary to earn a living in an agricultural society, and your deceased spouse’s family members were already people you knew. They already loved your children too.

Neither of these situations is historically unusual, but both are very difficult to determine using genetics alone, even in the current generation.

Neither X-DNA nor mitochondrial DNA will be helpful, and Y-DNA will generally not be either.

Unfortunately, three-quarter siblings’ autosomal DNA will fall in the range of both half and full siblings, although not at the bottom of the half-sibling range, nor at the top of the full sibling range – but that leaves a lot of middle ground.

I’ve found it almost impossible to prove this scenario without prior knowledge, and equally as impossible to determine which of multiple brothers is the father unless there is a very strong half-sibling match in addition.

The DNA-Sci blog discusses this phenomenon, but I can’t utilize comparison screenshots according to their terms of service.

Clearly, what we need are more known three-quarter siblings to submit data to be studied in order to (possibly) facilitate easier determination, probably based on the percentage frequency distribution of FIR/HIR segments. Regardless, it’s never going to be 100% without secondary genealogical information.

Three-quarter siblings aren’t very common today, but they do exist. If you suspect something of this nature, really need the answer, and have exhausted all other possibilities, I recommend engaging a very experienced genetic genealogist with experience in this type of situation. However, given the random nature of recombination in humans, we may never be able to confirm using any methodology, with one possible exception.

There’s one possibility using Y-DNA if the parents in question are two brothers. If one brother has a Y-DNA SNP mutation that the other does not have, and this can be verified by testing either the brothers who are father candidates or their other known sons via the Big Y-700 test – the father of the siblings could then be identified by this SNP mutation as well. Yes, it’s a long shot.

Three-quarter sibling situations are very challenging.

Step-siblings, on the other hand, are easy.

Step-Siblings

Step-siblings don’t share either parent, so their DNA will not match to each other unless their parents are somehow related to each other. Please note that this means either of their parents, not just the parents who marry each other.

One child’s parent marries the other child’s parent, resulting in a blended family. The children then become step-siblings to each other.

The terms step-sibling and half-sibling are often used interchangeably, and they are definitely NOT the same.

Adopted Siblings

Adopted siblings may not know they are adopted and believe, until DNA testing, that they are biological siblings.

Sometimes adopted siblings are either half-siblings or are otherwise related to each other but may not be related to either of their adoptive parents. Conversely, adopted siblings, one or both, may be related to one of their adoptive parents.

The same full and half-sibling relationship genetic clues apply to adopted siblings, as well as the tools and techniques in the In Search of Unknown Family series of articles.

Donor-Conceived Siblings

Donor-conceived siblings could be:

  • Half-siblings if the donor is the same father but a different mother.
  • Half-siblings if they share an egg donor but not a father.
  • Full siblings if they are full biological siblings to each other, meaning both donors are the same but not related to the woman into whom the fertilized egg was implanted, nor to her partner, their legal parents.
  • Not biologically related to each other or either legal parent.
  • Biologically related to one or both legal parents when a family member is either an egg or sperm donor.

Did I cover all of the possible scenarios? The essence is that we literally know nothing and should assume nothing.

I have known of situations where the brother (or brothers) of the father was the sperm donor, so the resulting child or children appear to be full or three-quarters siblings to each other. They are related to their legal father who is the mother’s partner. In other words, in this situation, the mother’s husband was infertile, and his brother(s) donated sperm resulting in multiple births. The children from this family who were conceived through different brothers and had very close (half-sibling) matches to their “uncles'” children were very confused until they spoke with their parents about their DNA results.

The same techniques to ascertain relationships would be used with donor-conceived situations. Additionally, if it appears that a biological relationship exists, but it’s not a full or half-sibling relationship, I recommend utilizing other techniques described in the In Search of Unknown Family series.

Twins or Multiple Birth Siblings

Two types of twin or multiple birth scenarios exist outside of assisted fertilization.

Fraternal twins – With fraternal or dizygotic twins, two eggs are fertilized independently by separate sperm. Just view this as one pregnancy with two siblings occupying the same space for the same 9 months of gestation. Fraternal twins can be male, female or one of each sex.

Fraternal twins are simply siblings that happen to gestate together and will match in the same way that full siblings match.

Please note that it’s possible for two of a woman’s eggs to be fertilized at different times during the same ovulation cycle, potentially by different men, resulting in twins who are actually half-siblings.

A difference in ethnicity is NOT a reliable indicator of fraternal or identical twins. Submitting your own DNA twice often results in slightly different ethnicity results.

Identical twins – Identical or monozygotic twins occur when one egg is fertilized by one sperm and then divides into multiple embryos that develop into different children. Those children are genetically identical since they were both developed from the same egg and sperm.

Two of the most famous identical twins are astronauts Mark and Scott Kelly.

Identical twins are the same sex and will look the same because they have the same DNA, except for epigenetic changes, but of course external factors such as haircuts, clothes and weight can make identical twins physically distinguishable from each other.

DNA testing companies will either identify identical twins as “self,” “identical twin” or “parent/child” due to the highest possible shared cM count plus fully matching FIR regions.

For identical twins, checking the FIR versus HIR is a positive identification as indicated above at GEDmatch with completely solid green FIR regions. Do not assume twins that look alike are identical twins.

Siblings

Whoever thought there would be so many kinds of siblings!

If you observe the need to educate about either sibling terminology or DNA identification methodologies, feel free to share this article. When identifying relationships, never assume anything, and verify everything through multiple avenues.

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So, You Want to Become a Professional Genetic Genealogist

I get asked quite often about what is required to become a professional genetic genealogist.

That’s actually two separate questions.

  • What is required to become a professional genealogist?
  • Then, what is required to specialize as a genetic genealogist?

What It’s Not

Before we have this discussion, I need to make sure that you understand that I’m NOT talking about forensics, meaning IGG, or investigative genetic genealogy in this article.

  • This is NOT forensics (IGG)
  • This is also not a specialty in finding missing parents for adoptees and others searching for unknown parents.

Both IGG and adoption searches utilize the same methodology, a subset of genetic genealogy. I wrote about that in Identifying Unknown Parents and Individuals Using DNA Matching.

The difference between genetic genealogy more broadly and IGG is:

  • What you’re searching for
  • The perspective
  • The methods utilized.

Essentially, the functional difference is that genealogists know who they are and have some information about their ancestors. For example, they know who their parents are and probably at least their grandparents. Genealogists are using both DNA testing and traditional genealogical paper trail research methods to focus and make discoveries going backwards in time.

Both IGG and unknown parent research uses DNA and (sometimes some) paper trail genealogy to find ways to connect the closest matches to the DNA tester (or DNA sample) together to each other to identify either living or recently living people. For example, two people who are are first cousins to the tester should both have the same grandparents if they are related to the tester through the same parent.

If two people who are related to the tester as first cousins do not share the same grandparent(s), then they are related to the tester through different parents of the tester.

The commonality is that DNA testing and some types of records are used for:

  • IGG where you’re searching for the identity of the tester or DNA sample
  • Unknown parent(s) searches where you are searching for the identity of the parent(s)
  • Genetic genealogy

However, the search methodology is different for IGG and unknown parents than for genealogy.

With IGG and unknown parent searches, you’re looking for your closest matches, then attempting to connect them together to identify either currently living or recently living people.

This article focuses specifically on genealogy and genetic genealogy, meaning looking backwards in time to identify ancestors.

I wrote about the techniques used for both IGG and parental searching in the article, Identifying Unknown Parents and Individuals Using DNA Matching.

What Do Genealogists Do?

Genealogy is the study of family history and the descent of a person or a family. Genealogists use a variety of sources and methods to discover and show the ancestry of their subjects and in doing so, create the family trees that are familiar to all of us.

Genealogists use different sources and methods to find and show the descent and kinship of their subjects.

Traditional sources include but are not limited to the following record types:

  • Vital records (birth, marriage, and death certificates)
  • Census
  • Military
  • Immigration
  • Land and tax records
  • Wills and probate
  • Church records
  • Newspapers
  • Obituaries
  • Published and online books
  • Oral histories
  • Genealogy databases
  • And more

Of course, today the four types of DNA can be added to that list.

A professional genealogist needs to know how and where to find these types of records in the target area, any unique cultural or regional factors affecting those records, and how to interpret them both individually and together.

For example, in a deed record in colonial Virginia, why would, or wouldn’t a female release her dower right? What is dower right, and why is it important? How might that record, or lack thereof, affect future probate for that woman/couple? In what type of historical or court record book might one look for these types of records?

Genealogists also need to know how to weigh different types of information in terms of potential accuracy and how to interpret primary and secondary sources.

Primary sources are those that were created at or near the time of an event by someone who was present at the event or who had first-hand knowledge of it. Examples of primary sources include birth certificates, marriage licenses, and census records, although census records are far more likely to be inaccurate or incomplete than a birth certificate or marriage record. Genealogists need to understand why, and where to look for corroboration. Primary sources are considered to be most accurate.

Secondary sources are those that were created later by someone who did not have first-hand knowledge of the event. Examples of secondary sources include family histories and genealogies, published biographies, and sometimes, newspaper articles.

The genealogists “go to” source for understanding and interpreting evidence is Evidence Explained by Elizabeth Shown Mills, available here.

Of course, DNA understanding and analysis needs to be added to this list and has become an important resource in genealogy. Additionally, genetic genealogy has become a specialty within the broader field of genealogy, as has IGG.

Put another way, a genealogist should have expertise and a specialty in some area. Maybe Italian records, or Native American genealogy, or New England records, in addition to the basic skills. At one time, a genealogist didn’t necessarily HAVE TO have expertise in genetic genealogy as well, but that has changed in the past few years. A professional genealogist should MINIMALLY understand the basics of genetic genealogy and when/how it can be useful. They may or may not have ready access to a genetic genealogist within the company where they work.

Being an independent genealogist, unless you specialize only in a specific area, like Dutch genealogy, is much more challenging because you’ll need to be proficient in BOTH Dutch genealogy AND genetic genealogy. It’s tough keeping up with one specialty, let alone two, although in this case, Yvette does an amazing job. However, her primary specialty is Dutch genealogy, and genetic genealogy is the booster rocket when appropriate. Genetic genealogy is not always needed for traditional genealogy, which is why genetic genealogy is a specialty skill.

In addition to all that, you also need to be proficient and comfortable with technology and a good communicator. Walking on water is also helpful:)

Job Description

So, what does the job description for a genealogist look like?

I reached out to Legacy Tree Genealogists because they are one of the largest, if not the largest genealogy research company, and they partner with 23andMe, FamilyTreeDNA, and MyHeritage. Legacy Tree has specialists in many regions and languages, in addition to six genetic genealogists on staff.

Fortunately, they have a job listing posted right now, here, with an excellent description of what is expected.

If you’re interested or wish to sign up for notifications, click here.

Understanding that this job description won’t be posted forever, I reached out to the owner, Jessica Dalley Taylor, and asked if she would send me a sample description to include in this article.

Here you go, courtesy of Jessica:

About You

It’s not easy to make each client’s experience the very best it can possibly be, and it means we can only hire an exceptional genealogist for this position. You will be a great fit if:

    • You are fluent in English and can explain your genealogy discoveries in a way that clients connect with and understand
    • You have taken at least one genetic genealogy test or administered the test of a relative
    • You have introductory genetic genealogy abilities
    • You have at least intermediate traditional genealogical research experience in any geographic locality
    • You are familiar with the repositories of the areas for which you claim expertise and have worked with them to obtain documents
    • You are passionate about genealogy and are a creative problem solver
    • You are great at working independently and hitting deadlines (please don’t overlook this line about deadlines)
    • You are comfortable with Microsoft Office suite
    • You’re familiar with genealogical technology such as pedigree software
    • You have a quiet place to work without distractions, a computer, and great internet
    • You have a strong desire to work as a professional genetic genealogist

Even better if:

    • You have a basic understanding of genetic inheritance and its application to genealogy
    • You have beginning experience with interpretation and use of genetic genealogy test results
    • You have intermediate-level genetic genealogy abilities

What you’ll be doing at Legacy Tree:

    • You’ll be learning how to use genetic testing in identifying family
    • You’ll be learning how to create high-quality research reports
    • You’ll be reading and formatting reports by professional researchers
    • You’ll be assisting with researching and writing genealogy reports
    • You’ll be performing genetic genealogy analysis under the direction of professional mentors
    • You’ll be developing advanced-level genetic genealogy skills and abilities
    • With your input, you’ll do other things as opportunities and needs arise

Please note that Legacy Tree offers both traditional genealogy services, combined with genetic genealogy, along with adoption and unknown parent searches.

As a measure of fundamental basic genetic genealogy skills, you should be able to create and teach a class like First Steps When Your DNA Results Are Ready – Sticking Your Toe in the Genealogy Water.

You should also be able to read and fully comprehend the articles on this blog, as well as explain the content to others. A very wise person once told me that if you can’t explain or teach a topic, you don’t understand it.

As luck would have it, Ancestry also posted a job opening for a genealogist as I was finishing this article. Here’s part of the job requirements.

Contractor or Employee

Please note that many companies have shifted their primary hiring strategy to utilizing contractors for not more than half time, especially now that working remotely has become the norm.

This may or may not be good news for you.

It allows the company to avoid paying benefits like insurance, vacation, leave, and retirement programs which reduces their costs. You may not need these benefits, and it may represent an opportunity for you. For others who need those benefits, it’s a deal-breaker.

Contracting may provide the ability to work part-time, but contracting probably means you need to have business management skills not required when you work for someone else. Let’s just say that I make quarterly estimated tax payments and my annual CPA bill is in the $2,000 range.

Compensation

Pay, either as an employee or contractor for a company, is a sticky wicket in this field.

First, there’s a consumer mindset, although not universal, that genealogy “should be” free. In part, this is due to search angels and a history of well-intentioned people making things free. I’m one of them – guilty as charged – this blog is free. My hourly work, however, when I accepted clients (which I DO NOT now,) was not free.

However, that “should be free” mindset makes it difficult to shift to a “pay to play” mentality when people can go on social media and get what they want for free.

Professional services are not and should not be free.

Professionals should be able to earn a respectable living. The full-time Ancestry job, posted above, with those credentials, nets out to $21.63 per hour for a 40-hour week, with a graduate degree preferred. For comparison, google other jobs and professions.

If you doubt for one second whether professional services should or should not be free, especially ones that require a bachelor’s degree or master’s, just think about what your CPA would do if you asked them to do your taxes because they have the ability, for free. Same for a doctor, lawyer, or any other professional.

People are often shocked at the rates paid to employees versus the rates charged to prospective customers. This discussion has recently gotten spicy on social media, so I’m not going to comment other than to say that when I did take private clients, which I DO NOT ANYMORE, I found it much more beneficial to operate independently than to work for a company.

However, I also had a readily recognizable specialty and an avenue to reach potential clients.

I also already had a business structure set up, and a CPA, and perhaps more important than either of those – I had medical insurance already in place.

The need for benefits is what drives many people to work for companies, which I fully understand. It’s also a big factor in why there are more female genealogists than male genealogists. Married women in the US are eligible to be covered by their spouse’s insurance, assuming the spouse has insurance through their employer.

My very strong recommendation to you is to weigh all of the factors and NEVER to find yourself without medical insurance or coverage.

If you’re going to be “self-employed,” set up a company. If you’re going to set up a company, do it properly, understand the tax ramifications of the various types of corporations and engage a competent CPA to shepherd you through the process from day 1 through taxes. They are worth every penny.

Look at various jobs in the market, review at the associated pay, get a quote for genealogy services of the type you would be providing from the various companies – and decide if this profession is really for you.

I don’t mean to be a wet blanket, just a realist.

Training and Certification

Now for the good news and the bad news.

  • There is professional training for genealogy
  • There are certifications for genealogy
  • There is no “one place” for either
  • There is no certification for genetic genealogy
  • There’s a LOT of misunderstanding and misinformation about genetic genealogy
  • Genetic genealogy changes often

You need to view your education for genealogy/genetic genealogy in the same way you’d view obtaining a college degree – plus continuing education to maintain your education and skills at a current and functional level.

And yes, all of that costs money. If you decide to work for a company, be sure to ask if continuing ed is on their dime and time, or yours.

Genealogy Training

The Board for Certification of Genealogists, BCG, allows graduates to append CG, for Certified Genealogist after their name. BCG is focused on certification of skills and is not a training platform, although they do provide some webinars, etc. It’s not a college curriculum though. Certification is the “end game” for many. Candidates must submit a portfolio for evaluation, complete in a specific timeframe, and must reapply every five years to maintain their certification.

Not all genealogists are certified by BCG, and BCG only lists references of BCG members.

In the field of Genetic Genealogy, that can be problematic because many competent and well-known people are not BCG certified. BCG does not have a genetic genealogy certification.

Lack of BCG certification does not mean that someone is not qualified, and BCG certification certainly does NOT mean or imply that the individual is competent in genetic genealogy, which has more and more become a part of almost every genealogical puzzle. If not for initial discovery, for confirmation.

There are many avenues for genealogical training, including, but not limited to:

  • Brigham Young University Family History Degree
  • NGS Home Study Course
  • Salt Lake Institute of Genealogy (SLIG)
  • Genealogical Research Institute of Pittsburgh (GRIP)
  • Boston University Certificate program
  • Genealogical Institute on Federal Records (Gen-Fed)
  • Institute of Genealogy and Historical Research (IGHR)
  • University of Strathclyde
  • University of Dundee
  • Major Conferences, including RootsTech and NGS, among others
  • Specialty conferences such as the International Conference on Jewish Genealogy (IAJGS)
  • Online conferences and conference proceedings such as Rootstech who maintains a free library of their virtual and recorded conference sessions.
  • Legacy Family Tree Webinars
  • Videos produced by major genealogy companies such as MyHeritage, FamilyTreeDNA and Ancestry, often available through their website, Youtube or both
  • Blogs and learning/help centers of the major genealogy companies

Genetic Genealogy Training

Genetic genealogy training is more challenging because there is no specific program, curriculum, or certification.

Many genetic genealogists obtained their experience as a part of genealogy over 15 or 20 years and have focused on the genetic aspect of genealogy. Several of us had a scientific background that meshed well with this field and is part of why we discovered that our passion is here.

Before I provide this resource list, I need to emphatically state that probably 95% of answers that I see provided on social media platforms in response to questions asked by people are either entirely incorrect, partially incorrect in a way that makes me want to say, “well, not exactly,” or are incomplete in a way that makes a significant difference.

I chose and choose to focus on creating educational tools and making explanations available for everyone, in one place, not one question at a time.

I began publishing my blog in 2012 as an educational tool and I’m dumbstruck by how many people just want a yes or no answer instead of learning. If one doesn’t take the time to learn, they have no idea if the answers they receive are valid, or if there’s more to the story that they are missing.

Social media can mislead you badly if you don’t have the ability to discern between accurate answers, partially accurate answers, and incorrect answers. Furthermore, opinions differ widely on some topics.

Unfortunately, because there is no genetic genealogy credentialling, there is also no “post-nominal letters,” such as CG for certified genealogist. Therefore, a novice has absolutely no idea how to discern between an expert and another overly helpful novice who is unintentionally providing incorrect or partial information.

Many of us who at one time reliably answered questions have simply gotten burned out at the same question being asked over and over, and no longer regularly engage. Burnout is real. Another issue is that askers often don’t provide enough, or accurate, information, so a significant amount of time is spent in clarifying the information around a question. Furthermore, your CPA, lawyer, and physician don’t answer questions online for free, and neither do most people who are busy earning a living in this field.

DNA educational opportunities, some of which are contained within larger conference agendas, include:

There are other blogs, of course, some of which were launched by well-known genetic genealogists but are no longer maintained. Blogging is quite time-consuming.

I’ve covered all kinds of genetic genealogy topics in my blog articles. They are a good source of information, education and hands-on training. I attempt to publish two articles weekly, and there are over 1600 available for your enjoyment.

In addition to the initial learning period, you’ll need to make time to stay engaged and maintain your genealogy and genetic genealogy skills.

Apprenticeship

In addition to training, I think you’d need at least a year interning or working at a junior learning level, minimum. Think of it as your genealogy residency.

  • You could choose to work for a vendor in their help center.
  • You could choose to work for a genealogy company. I’ve mentioned the largest ones, but there are others as well.
  • You could choose to work on your own case studies and those of your friends and family, but if you do, be aware that you won’t have anyone reviewing your work. If you make a mistake or should have approached something differently, and you’re working alone, there’s no one to tell you.
  • You could work as a search angel for others. I have mixed emotions about this, in part due to the lack of review and oversight. But also, in part because “free search angels” perpetuate the idea that genealogy “should be” free.

If you want to work in IGG, after training, an internship under an established mentor is ABSOLUTELY ESSENTIAL for a minimum of 100 or so successful closures.

Genealogists and genetic genealogists have the ethical responsibility to NOT MAKE MISTAKES when working on other people’s family. You need to know what you know, what you don’t know, when to get help, from where and with whom.

Networking Opportunity

A Facebook group named “Genealogy Jobs” has been established to discuss opportunities and all of the topics surrounding this subject.

There’s a Genealogy Career Day event on April 22nd where you can interact with professionals including authors, freelance genealogists, certified genealogists, business owners, and an investigative genetic genealogist. Take a look at the topics. If you’re considering whether or not you want to go pro, you’ll be interested. You can sign up here.

The sessions will be uploaded to their YouTube channel, here, after the event.

I hope you’ve found this article useful and helps you decide if this profession is for you. If so, create a plan and execute.

If you decide you do want to go pro, I wish you the best and welcome you to the fast-paced world of professional genealogy or its specialty, genetic genealogy.

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X Chromosome Master Class

The X chromosome can be especially useful to genetic genealogists because it has a unique inheritance path. Thanks to that characteristic, some of the work of identifying your common ancestor is done just by simply HAVING an X match.

Unfortunately, X-DNA and X matching is both underutilized and somewhat misunderstood – in part because not all vendors utilize the X chromosome for matching.

The X chromosome has the capability of reaching further back in time and breaking down brick walls that might fall no other way.

Hopefully, you will read this article, follow along with your own DNA results and make important discoveries.

Let’s get started!

Who Uses the X Chromosome?

The X chromosome is autosomal in nature, meaning it recombines under some circumstances, but you only inherit your X chromosome from certain ancestors.

It’s important to understand why, and how to utilize the X chromosome for matching. In this article, I’ve presented this information in a variety of ways, including case studies, because people learn differently.

Of the four major testing vendors, only two provide X-DNA match results.

  • FamilyTreeDNA – provides X chromosome results and advanced matching capabilities including filtered X matching
  • 23andMe – provides X chromosome results, but not filtered X matching without downloading your results in spreadsheet format
  • Ancestry and MyHeritage do not provide X-DNA results but do include the X in your raw DNA file so you can upload to vendors who do provide X matching
  • GEDmatch – not a DNA testing vendor but a third-party matching database that provides X matching in addition to other tools

It’s worth noting at this point that X-DNA and mitochondrial DNA is not the same thing. I wrote about that, here. The source of this confusion is that the X chromosome and mitochondrial DNA are both associated in some way with descent from females – but they are very different and so is their inheritance path.

So, what is X-DNA and how does it work?

What is X-DNA?

Everyone inherits two copies of each of chromosomes 1-22, one copy of each chromosome from each of your parents.

That’s why DNA matching works and each match can be identified as “maternal” or “paternal,” depending on how your match is related to you. Each valid match (excluding identical by chance matches) will be related either maternally, or paternally, or sometimes, both.

Your 23rd chromosome is your sex determination chromosome and is inherited differently. Chromosome 23 is comprised of X and Y DNA.

Everyone inherits one copy of chromosome 23 from each parent.

  • Males inherit a Y chromosome from their father, which is what makes males male. They do not inherit an X chromosome from their father.
  • Males always inherit an X chromosome from their mother.
  • Females inherit an X chromosome from both parents, which is what makes them female. Females have two X chromosomes, and no Y chromosome.
Chromosome 23 Father Contributes Mother Contributes
Male Child Y chromosome X chromosome
Female Child X chromosome X chromosome

X-DNA and mitochondrial DNA are often confused, but they are not the same thing. In fact, they are completely different.

Mitochondrial DNA, in BOTH males and females is always inherited from only the mother and only descends from the direct matrilineal line, so only the mother’s mother’s mother’s direct line. X DNA can be inherited from a number of ancestors based on a specific inheritance path.

Everyone has both X-DNA AND mitochondrial DNA.

Because males don’t inherit an X chromosome from their father, X chromosome matching has a unique and specific pattern of descent which allows testers who match to immediately eliminate some potential common ancestors.

  • Males only inherit an X chromosome from their mother, which means they can only have legitimate X matches on their mother’s side of their tree.
  • Females, on the other hand, inherit an X chromosome from both their mother and father. Their father only has one X chromosome to contribute, so his daughter receives her paternal grandmother’s X chromosome intact.
  • Both males and females inherit their mother’s X chromosome just like any of the other 22 autosomes. I wrote about chromosomes, here.

However, the unique X chromosome inheritance path provides us with a fourth very useful type of DNA for genealogy, in addition to Y-DNA, mitochondrial and autosomal DNA.

For the vendors who provide X-matching, it’s included with your autosomal test and does not need to be purchased separately.

The Unique X Chromosome

The X chromosome, even though it is autosomal in nature, meaning it does recombine and divide in certain circumstances, is really its own distinct tool that is not equivalent to autosomal matching in the way we’re accustomed. We just need to learn about the message it’s delivering and how to interpret X matches.

FamilyTreeDNA is one of two vendors who utilizes X chromosome matching, along with 23andMe, which is another good reason to encourage your matches at other vendors to upload their DNA file to FamilyTreeDNA for free matching.

The four major vendors do include X-DNA results in their raw DNA download file, even if they don’t provide X-matching themselves. This means you can upload the results to either FamilyTreeDNA or GEDmatch where you can obtain X matches. I provided step-by-step download/upload instructions for each vendor here.

Let’s look how X matching is both different, and beneficial.

My X Chromosome Family Tree

We are going to build a simple case study. A case study truly is worth 1000 descriptions.

This fan chart of my family tree colorizes the X chromosome inheritance path. In this chart, males are colored blue and females pink, but the salient point is that I can inherit some portion of (or all of) a copy of my X chromosome from the colorized ancestors, and only those ancestors.

Because males don’t inherit an X chromosome from their father, they CANNOT inherit any portion of an X chromosome from their father’s ancestors.

Looking at my father’s half of the chart, at left, you see that I inherited an X chromosome from both of my parents, but my father only inherited an X chromosome from his mother, Ollie Bolton. His father’s portion of the tree is uncolored, so no X chromosome could have descended from his paternal ancestors to him. Therefore he could not pass any X chromosome segments to me from his paternal side – because he doesn’t have X DNA from his father.

Hence, I didn’t inherit an X chromosome from any of the people whose positions in the chart are uncolored, meaning I can only inherit an X chromosome from the pink or blue people.

Essentially any generational male to male, meaning father/son relationship is an X-DNA blocker.

I know positively that I inherited my paternal grandmother, Ollie Bolton’s entire X chromosome, because hers is the only X chromosome my father, in the fan chart above, had to give me. His entire paternal side of the fan chart is uncolored.

Men only ever inherit their X chromosome from their mother. The only exception to this is if a male has the rare genetic condition of Klinefelter Syndrome, also known as XXY. If you are an adult male, it’s likely that you’ll already know if you have Klinefelters, so that’s probably the last possibility you should consider if you appear to have paternal X matches, not the first.

Sometimes, men appear to have X matches on their father’s side, but (barring Klinefelter’s) this is impossible. Those matches must either be identical by chance, or somehow related in an unknown way on their mother’s side.

Everyone inherits an X chromosome from their mother that is some combination of the X from her father and mother. It’s possible to inherit all of your maternal grandmother or maternal grandfather’s X chromosome, meaning they did not recombine during meiosis.

Using DNA Painter as an X Tool

I use DNAPainter to track my matches and correlate segments with ancestors.

I paint my DNA segments for all my chromosomes at DNAPainter which provides me with a central tracking mechanism that is visual in nature and allows me to combine matches from multiple vendors who provide segment information. I provide step-by-step instructions for using DNAPainter, here.

This is my maternal X chromosome with my matches painted. I’ve omitted my matches’ names for privacy.

On the left side of the shaded grey column, those matches are from my maternal grandmother’s ancestors. On the right side, those matches are from my maternal grandfather’s ancestors.

The person in the grey column descends from unknown ancestors. In other words, I can tell that they descend from my maternal line, but I can’t (yet) determine through which of my two maternal grandparents.

There’s also an area to the right of the grey column where there are no matches painted, so I don’t know yet whether I inherited this portion of my X chromosome from my maternal grandmother or maternal grandfather.

The small darker pink columnar band is simply marking the centromere of the chromosome and does not concern us for this discussion.

Click on any image to enlarge

In this summary view of my paternal X chromosome, above, it appears that I may well have inherited my entire X chromosome from my paternal great-grandmother. We know, based on our inheritance rules that I clearly received my paternal grandmother’s X chromosome, because that’s all my father had to give me.

However, by painting my matches based on their ancestors, and selecting the summary view, you can see that most of my paternal X chromosome can be accounted for, with the exception of rather small regions with the red arrows.

It’s not terribly unusual for either a male or female to inherit their entire maternal X chromosome from one grandparent, or in this case, great-grandparent.

Of course, a male doesn’t inherit an X chromosome from their father, but a female can inherit her paternal X chromosome from either or both paternal grandparents.

Does Size Matter?

Generally speaking, an X match needs to be larger than a match on the other chromosomes to be considered genealogically equivalent in the same timeframe as other autosomal matches. This is due to:

  • The unique inheritance pattern, meaning fewer recombination events occurred.
  • The fact that X-DNA is NOT inherited from several lines.
  • The X chromosome has lower SNP density, meaning it contains fewer SNPs, so there are fewer possible locations to match when compared to the other chromosomes.

I know this equivalency requirement sounds negative, but it’s actually not. It means 7 cM (centimorgans) of DNA on the X chromosome will reach back further in time, so you may carry the DNA of an ancestor on the X chromosome that you no longer carry on other chromosomes. It may also mean that older segments remain larger. It’s actually a golden opportunity.

It sounds much more positive to say that a 16 cM X match for a female, or a 13 cM X match for a male is about the same as a 7 cM match for any other autosomal match in the same generation.

Of course, if the 7 cM match gets divided in the following generation, it has slipped below the matching threshold. If a 16 or 13 cM X match gets divided, it’s still a match. Plus, in some generations, if passed from father to daughter, it’s not divided or recombined. So a 7 cM X match may well be descended from ancestors further back in time.

X Chromosome Differences are Important!

Working with our great-great grandparent’s generation, we have 16 direct ancestors as illustrated in the earlier fan chart.

Given that females inherit from 8 X-chromosome ancestors in total, they are going to inherit an average of 45.25 cM of X-DNA from each of those ancestors. Females have two X chromosomes for a total length of 362 cM of X-DNA from both parents.

A male only has one X chromosome, 181 cM in length, so he will receive an average of 36.2 cM from each of 5 ancestors, and it’s all from his mother’s side.

In this chart, I’ve shown the total number of cMs for all of the autosomes, meaning chromosomes 1-22 and, separately, the X for males and females.

  • The average total cM for chromosomes 1-22 individually is 304 cM. (Yes, each chromosome is a different length, but that doesn’t matter for averages.)
  • That 304 cM can be inherited from any of 16 ancestors (in your great-grandparent’s generation)
  • The total number of cM on the X chromosomes for both parents for females totals 362
  • The total cM of X-DNA for males is 181 cM
  • The calculated average cM inherited for the X chromosome in the same generation is significantly different, shown in the bottom row.

The actual average for males and females for any ancestor on any random non-X chromosome (in the gg-grandparent generation) is still 19 cM. Due to the inheritance pattern of the X chromosome, the female X-chromosome average inheritance is 45.25 cM and the male average is 36.2 cM, significantly higher than the average of 19 cM that genetic genealogists have come to expect at this relationship distance on the other chromosomes, combined.

How Do I Interpret an X Match?

It’s important to remember when looking at X matching that you’re only looking at the amount of DNA from one chromosome. When you’re looking at any other matching amount, you’re looking at a total match across all chromosomes, as reported by that vendor. Vendors report total matching DNA differently.

  • The total amount of matching autosomal DNA does not include the X chromosome cMs at FamilyTreeDNA. X-DNA matching cMs are reported separately.
  • The total amount of matching autosomal DNA does include the X chromosome cMs in the total cM match at 23andMe
  • X-DNA is not used for matching or included in the match amount at either MyHeritage or Ancestry, but is included in the raw DNA data download files for all four vendors.
  • The total match amount shows the total for 22 (or 23) chromosomes, NOT just the X chromosome(s). That’s not apples to apples.

Therefore, an X match of 45 cM for a female or 36 for a male is NOT (necessarily) equivalent to a 19 cM non-X match. That 19 cM is the total for 22 chromosomes, while the X match amount is just for one chromosome.

You might consider a 20 cM match on the regular autosomes significant, but a 20 cM X-only match *could* be only roughly equivalent to a 10ish cM match on chromosomes 1-22 in the same generation. That’s the dog-leg inheritance pattern at work.

This is why FamilyTreeDNA does not report an X-only match if there is no other autosomal match. A 19 cM X match is not equivalent to a 19cM match on chromosomes 1-22. Not to mention, calculating relationships based on cM ranges becomes more difficult when the X is included.

However, the flip side is that because of the inheritance pattern of the X chromosome, that 19 cM match, if valid and not IBC, may well reach significantly further back in time than a regular autosomal matches. This can be particularly important for people seeking either Native or enslaved African ancestors for whom traditional records are elusive if they exist at all.

Critical Take-Away Messages

Here are the critical take-away messages:

  1. Because there are fewer ancestral lineages contributing to the tester’s X chromosome, the amount of X chromosomal DNA that a tester inherits from the ancestors who contribute to their X chromosome is increased substantially.
  2. The DNA of the contributing ancestors is more likely to be inherited, because there are fewer other possible contributing ancestors, meaning fewer recombination events or DNA divisions/recombinations.
  3. X-DNA is also more likely to be inherited because when passed from mother to son, it’s passed intact and not admixed with the DNA of the father.
  4. X matches cannot be compared equally to either percentages or cM amounts on any of the other chromosomes, or autosomal DNA in total, because X matching only reports the amount on one single chromosome, while your total cM match amount reports the amount of DNA that matches from all chromosomes (which includes the X at 23andMe).
  5. If you have X matches at 23andMe and/or FamilyTreeDNA, you can expect your total matching to be higher at 23andMe because they include the X matching cM in the total amount of shared DNA. FamilyTreeDNA provides the amount of X matching DNA separately, but not included in the total. MyHeritage and Ancestry do not include X matching DNA.

For clarity, at FamilyTreeDNA, you can see my shared DNA match with my mother. Of course, I match her on the total length of all my chromosomes, which is 3563 cM, the total Shared DNA for chromosomes 1-22. This includes all chromosomes except for the X chromosome which is reported separately at 181 cM. The longest contiguous block of shared DNA is 284 cM, the entire length of chromosome 1, the longest chromosome.

Because I’m a female, I match both parents on the full length of all 23 chromosomes, including 181 cM on both X chromosomes, respectively. Males will only match their mother on their X chromosome, meaning their total autosomal DNA match to their father, because the X is excluded, is 181 cM less than to their mother.

This difference in the amount of shared DNA with each parent, plus the differences in how DNA totals are reported by various vendors is also challenging for tools like DNAPainter’s Shared cM Tool which is based on the crowd sourced Shared cM Project that averages shared DNA numbers for known relationships at various vendors and translates those numbers into possible relationships for unknown matches.

Not all vendors report their total amount of shared DNA the same way. This is true for both X-DNA and half identical (HIR) versus fully identical (FIR) segments at 23andMe. This isn’t to say either approach is right or wrong, just to alert you to the differences.

Said Another Way

Let’s look at this another way.

If the average on any individual chromosome is 19 cMs for a relationship that’s 5 generations back in time. The average X-DNA for the same distance relationship is substantially more, which means that:

  • The X-DNA probably reaches further back in time than an equivalent relationship on any other autosome.
  • The X-DNA will have (probably) divided fewer times, and more DNA will descend from individual ancestors.
  • The inheritance path, meaning potential ancestors who contributed the X chromosomal DNA, is reduced significantly.

It’s challenging to draw equivalences when comparing X-DNA matching to the other chromosomes due to several variables that make interpretation difficult.

Based on the X-match size in comparison to the expected 19 cM single chromosome match at this genealogical distance, what is the comparable X-DNA segment size to the minimum 7 cM size generally accepted as valid on other chromosomes? What would be equal to a 7 cM segment on any other single random autosomal match, even though we know the inheritance probabilities are different and this isn’t apples to apples? Let’s pretend that it is.

This calculation presumes at the great-great-grandparent level that the 19 cM is in one single segment on a single chromosome. Now let’s divide 19 cM by 7 cM, which is 2.7, then divide the X amounts by the same number for the 7 cM equivalent of 16.75 cM for a female and 13.4 cM for a male.

When people say that you need a “larger X match to be equivalent to a regular autosomal match,” this is the phenomenon being referenced. Clearly a 7 cM X match is less relevant, meaning not equivalent, in the same generation as a 7 cM regular autosomal match.

Still, X matching compared to match amounts shown on the other chromosomes is never exact;u apples to apples because:

  • You’re comparing one X chromosome to the combined DNA amounts of many chromosomes.
  • The limited recombination path.
  • DNA from the other autosomes is less likely to be inherited from a specific ancestor.
  • The X chromosome has a lower SNP density than the other chromosomes, meaning fewer SNPs per cM.
  • The X-DNA may well reach further back in time because it has been divided less frequently.

Bottom Line

The X chromosome is different and holds clues that the other autosomes can’t provide.

Don’t dismiss X matches even if you can’t identify a common ancestor. Given the inheritance path, and the reduced number of divisions, your X-DNA may descend from an ancestor further back in time. I certainly would NOT dismiss X matches with smaller cMs than the 13 and 16 shown above, even though they are considered “equivalent” in the same generation.

X chromosome matching can’t really be equated to matching on the other chromosomes. They are two distinct tools, so they can’t be interpreted identically.

Different vendors treat the X chromosome differently, making comparison challenging.

  • 23andMe includes not only the X chromosome in their cM total, but doubles the Fully Identical Regions (FIR) when people, such as full siblings, share the same DNA from both parents. I wrote about that here.
  • Ancestry does not include the X in their cM match calculations.
  • Neither does MyHeritage.
  • FamilyTreeDNA shows an X match only when it’s accompanied by a match on another chromosome.

The Shared cM Project provides an average of all of the data input by crowdsourcing from all vendors, by relationship, which means that the cM values for some relationships are elevated when compared to the same relationship or even same match were it to be reported from a different vendor.

The Best Part!

The X chromosome inheritance pattern means that you’re much more likely to carry some amount of a contributing ancestor’s X-DNA than on any other chromosome.

  • X-DNA may well be “older” because it’s not nearly as likely to be divided, given that there are fewer opportunities for recombination.
  • When you’re tracking your X-DNA back in your tree, whenever you hit a male, you get an automatic “bump” back a generation to his mother. It’s like the free bingo X-DNA square!
  • You can immediately eliminate many ancestors as your most recent common ancestor (MRCA) with an X-DNA match.
  • Because X-DNA reaches further back in time, sometimes you match people who descend from common ancestors further back in time as well.

If you match someone on multiple segments, if one of those matching segments is X-DNA, that segment is more likely to descend from a different ancestor than the segments on chromosomes 1-22. I’ve found many instances where an X match descends from a different ancestor than matching DNA segments on the autosomes. Always evaluate X matches carefully.

Sometimes X-DNA is exactly what you need to solve a mystery.

Ok, now let’s step through how to use X-DNA in a real-life example.

Using X DNA to Solve a Mystery

Let’s say that I have a 30 cM X match with a male.

  • I know immediately that our most recent common ancestor (MRCA) is on HIS mother’s side.
  • I know, based on my fan chart, which ancestral lines are eliminated in my tree. I’ve immediately narrowed the ancestors from 16 to 5 on his side and 16 to 8 on my side.
  • Two matching males is even easier, because you know immediately that the common ancestor must be on both of their mother’s sides, with only 5 candidate lines each at the great-great-grandparent generation.

Female to female matches are slightly more complex, but there are still several immediately eliminated lines each. That means you’ve already eliminated roughly half of the possible relationships by matching another female on their X chromosome.

In this match with a female second cousin, I was able to identify who she was via our common ancestor based on the X chromosome path. In this chart, I’m showing the relevant halves of her chart at left (paternal), and mine (maternal), side by side.

I added blockers on her chart and mine too.

As it turns out, we both inherited most of our X chromosome from our great-grandparents, marked above with the black stars.

Several lines are blocked, and my grandfather’s X chromosome is not a possibility because the common ancestor is my maternal grandmother’s parents. My grandfather is not one of her ancestors.

Having identified this match as my closest relative (other than my mother) to descend on my mother’s maternal side, I was able to map that portion of my X chromosome to my great-grandparents Nora Kirsch and Curtis Benjamin Lore.

My X Chromosome at DNA Painter

Here’s my maternal X chromosome at DNAPainter and how I utilized chromosome painting to push the identification of the ancestors whose X chromosome I inherited back an additional two generations.

Using that initial X chromosome match with my second cousin, shown by the arrow at bottom of the graphic, I mapped a large segment of my maternal X chromosome to my maternal great-grandparents.

By viewing the trees of subsequent X maternal matches, I was then able to push those common segments, shown painted directly above that match with the same color, back another two generations, to Joseph Hill, born in 1790, and Nabby Hall. I was able to do that based on the fact that other matches descend from Joseph and Nabby through different children, meaning we all triangulate on that common segment. I wrote about triangulation at DNAPainter, here.

I received no known X-DNA from my great-grandmother, Nora Kirsch, although a small portion of my X chromosome is still unassigned in yellow as “Uncertain.”

I received a small portion of my maternal X chromosome, in magenta, at left, from my maternal great-great-grandparents, John David Miller and Margaret Lentz.

The X chromosome is a powerful tool and can reach far back in time.

In some cases, the X, and other chromosomes can be inherited intact from one grandparent. I could have inherited my mother’s entire copy of her mother’s, or her father’s X chromosome based on random recombination, or not. As it turns out, I didn’t, and I know that because I’ve mapped my chromosomes to identify my ancestors based on common ancestors with my matches.

X-DNA Advanced Matches at FamilyTreeDNA

At FamilyTreeDNA, the Advanced Matches tab includes the ability to search for X matches, either within the entire database, or within specific projects. I find the project selection to be particularly useful.

For example, within the Claxton project, my father’s maternal grandmother’s line, I recognize my match, Joy, which provides me an important clue as to the possible common ancestor(s) of our shared segments.

Joy’s tree shows that her 4-times great-grandparents are my 3-times great-grandparents, meaning we are 4th cousins once removed and share 17 cM of DNA on our X chromosome across two segments.

Don’t be deceived by the physical appearance of “size” on your chromosomes. The first segment that spans the centromere, or “waist” of the chromosome, above, is 10.29 cM, and the smaller segment at right is 7.02 cM. SNPs are not necessarily evenly distributed along chromosomes.

Remember, an X or other autosomal match doesn’t necessarily mean the entire match is contained in one segment so long as it’s large enough to be divided in two parts and survive the match threshold.

It’s worth noting that Joy and I actually share at least two different, unrelated ancestral lines, so I need to look at Joy’s blocked lines to see if one of those common ancestral lines is not a possibility for our X match. It’s important to evaluate all possible ancestors, plus the inheritance path to eliminate any lineage that involves a father to son inheritance on the X chromosome.

Last but not least, you may match on your X chromosome through a different ancestor than on other chromosomes. Every matching segment has its own individual history. It’s not safe to assume.

Now, take a look at your X chromosome matches at FamilyTreeDNA, 23andMe, and GedMatch. What will you discover?

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Chromosomes and Genealogy

Sometimes people ask about how chromosomes relate to genealogy. Every single one of us started with that question, right?

Are chromosomes different sizes, and does that matter? What are the mystery terms, cMs and SNPs? How does all of this intersect with genealogy? Do I care?

These are all great questions, and of course, there are different ways to answer. Let’s start with some basics.

Chromosomes 1-22

First, you have two copies of each of chromosomes 1-22.

The karyogram above, a photo taken through a microscope, courtesy of the National Human Genome Research Institute, shows the chromosomes of a human male. I’ve added the numbering and labeled the X and Y chromosomes (23).

You inherit one copy of each chromosome from each of your parents. You can see the two halves of each chromosome, above. One half of each chromosome is contributed by the person’s mother, and the other half is contributed by the father.

That’s why DNA matching works, and each match can be designated as “maternal” or “paternal,” depending on how your match is related to you.

Each match will be related either maternally, paternally, or sometimes, both. Of course, that’s presuming the matches are identical by descent, and not identical by chance, but that’s a different discussion. For this article, we’re referencing valid matches with whom you share common ancestors – whether you know who they are or not.

Your 23rd chromosome is different than chromosomes 1-22.

Chromosome 23 Determines a Child’s Sex

Your 23rd chromosome is your sex-determination chromosome and is inherited differently.

You still inherit one copy of chromosome 23 from each parent.

  • Males inherit a Y chromosome from their father, which is what makes males male.
  • Males inherit an X chromosome from their mother.
  • Females inherit an X chromosome from both parents, which makes them female.
Chromosome 23 Father Contributes Mother Contributes
Male Child Y chromosome X chromosome
Female Child X chromosome X chromosome

Because males don’t inherit an X chromosome from their father, X chromosome matching for genealogy has a unique and specific pattern of descent which allows testers to immediately eliminate some potential common ancestors.

The Y chromosome can be tested separately for males and follows the direct paternal line. You can read about the 4 Kinds of DNA for Genetic Genealogy, here.

The X chromosome is quite useful for genealogy due to its unique inheritance path and is included by both FamilyTreeDNA and 23andMe in matching.

Picture This

Three of the four major vendors, plus GEDmatch, provide a visual match depiction of your chromosomes using a chromosome browser:

Unfortunately, Ancestry does not provide a chromosome browser or segment location information.

Using your chromosomes as the canvas, matches to your father and mother are shown using the chromosome browser at FamilyTreeDNA, below.

You can see that a tester matches both parents on the entire covered region of all of their chromosomes. The beginning and the end tips of each chromosome sometimes aren’t covered, and neither are some other regions that are very SNP-location-poor. Omitted regions are shown by hashes. Regions that are light grey, but not hashed, are covered, but the match’s test didn’t produce results in that region.

This is why you may have a slightly different size match with one parent versus the other, especially if they both didn’t test at the same vendor at the same time.

The chromosome browser graphic visually answers the chromosome size question, but there’s more to this answer. It’s easy to see that there’s a significant difference in the physical chromosome size, but there’s more to the story.

SNPs – Chromosome Street Addresses

SNPs, known as Single Nucleotide Polymorphisms, are mutations recorded at specific addresses on chromosomes. Each chromosome holds a specific number of addresses that are read during sequencing and used for match comparison.

All of your other matches that are not parent-child and not your identical twin will match on some subset of these locations.

The Rest of the Answer – Centimorgans and SNPs

Centimorgans (cMs) are units of recombination used to measure genetic distance. You can read a scientific definition here.

For our conceptual purposes, think of centimorgans as lines on a football field. They represent distance on the chromosome.

SNPs are locations that are compared between two people to see if a match occurs.

Think of SNPs as addresses for blades of grass on that football field where an expected value occurs. If values at that address are different, then they don’t match. If values are the same, then they do match. For autosomal DNA matching, we look for long runs of SNPs that match between two people to confirm a common ancestor.

Think of SNPs as blades of grass growing between the lines on the football field. In some areas, especially in my yard, there will be many fewer blades of grass between those lines than there would be on either a well-maintained football field, or maybe a manicured golf course. You can think of the lighter green bands as sparse growth and the darker green bands as dense growth.

If the distance between 2 lines on the football field is 8 cM, for example, and there are 700 blades of grass growing there, you’ll be a match to another person if (almost) all of your blades of grass between those 2 lines match, assuming the match threshold is minimally 8 cM and 700 SNPs.

For purposes of autosomal DNA, the combination of centimorgans (distance,) and the number of SNPs (locations) within that distance measurement determines if someone is considered a match to you. In other words, you’re listed as a match if the shared DNA is over the minimum or selected thresholds. Think of track and field hurdles. To get to the end (a match), you have to get over all of the hurdles!

For example, a threshold of 8 cM and 700 SNPs means that anyone who matches you equal to or greater than both of these cumulative thresholds will be displayed as a match. Centimorgans and SNPs work in tandem to ensure valid matches.

A Second Yardstick

So, the second measure of chromosome size is the number of cMs from the beginning to the end of the chromosome, and the number of SNPs on that chromosome.

Different vendors, and different DNA testing chips cover slightly different regions. This is my match with my mother, which shows:

  • Total matching cMs on each chromosome
  • Total matching SNPs on each chromosome
  • SNP Density, which is a calculation (cM/SNPs) showing how “thick” the SNP grass is on each chromosome

The higher the matching number of cMs, especially in a row (longest segment,) the higher quality the match, and the closer the relationship.

Note that endogamous, or intermarried populations, may need separate interpretations. I discussed the signs of endogamy in this article.

Calculating Matches

Some vendors provide the ability to select your match cM and SNP thresholds, and others make those selections for you. Most vendors no longer display the number of matching SNPs, given that SNP-poor regions are, for the most part, automatically eliminated, although you can view them in your matching segment download file. In other words, the vendors simply take care of this for you. The accepted rule of thumb has always been that 500 (some said 700) or fewer SNPs was too small to be genealogically relevant, regardless of the cM match size.

Vendors include numerous and varying factors in determining match quality and potential relationships, including:

  • Total shared DNA, meaning total matching cM
  • Longest shared, meaning contiguously matching DNA block
  • X matching
  • Sex of tester (especially with respect to X matching)
  • Endogamy flags
  • Half versus fully identical DNA regions (to positively identify relationships such as half vs full siblings)
  • Triangulated segments
  • Family Matching (maternal and paternal bucketing) at FamilyTreeDNA
  • Tree matching

Not all vendors include all factors, and each vendor utilizes proprietary algorithms for features like triangulation.

The question isn’t chromosome size or even match size alone, but the quality of the match plus additive genealogical features like Theories of Family Relativity at MyHeritage to identify common and even previously unknown ancestors.

Be sure to test at the primary vendors or upload for free to MyHeritage, FamilyTreeDNA and GEDmatch to receive as many matches as possible. You just never know where that match you really need is hiding!

Enjoy!

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Thank you so much.

DNA Purchases and Free Uploads

Genealogy Products and Services

My Book

Genealogy Books

Genealogy Research

DNA Black Friday is Here

Yes, I know it’s not Friday yet, but the DNA Black Friday sales have started, and sale dates are limited, so here we go.

These are the best prices I’ve ever seen at both FamilyTreeDNA and MyHeritage. If you’ve been waiting to purchase a DNA test for that special someone, there’s never been a better time.

Remember, to jump-start your genetic genealogy, test close or targeted relatives in addition to yourself:

  • Parents, or if both parents are not available, full and half-siblings
  • If neither parents nor siblings are available, your siblings’ descendants
  • Grandparents or descendants of your grandparents – aunts, uncles, or their descendants
  • Cousins descended from great-grandparents or other known ancestors
  • Y and mitochondrial DNA descendants of specific, targeted ancestors

For yourself, you’ll want to fish in all the ponds by taking an autosomal test or uploading a DNA file to each of the four vendors. Upload/download instructions are available here.

Everyone can test their own mitochondrial DNA to learn about your mother’s direct matrilineal line, and males can test their Y-DNA to unveil information about their patrilineal or surname line. Women, you can test your father’s, brother’s, or paternal uncle’s Y-DNA.

I’ve written a DNA explainer article, 4 Kinds of DNA for Genetic Genealogy, which you might find helpful. Please feel free to pass it on.

Vendor Offerings

FamilyTreeDNA

Free shipping within the US for orders of $79 or more

FamilyTreeDNA is the only major testing company that offers multiple types of tests, meaning Y-DNA, mitochondrial and autosomal. You can also get your toes wet with introductory level tests for Y DNA (37 and 111 marker tests), or you can go for the big gun right away with the Big Y-700.

This means that if you’ve purchased tests in the past, you can upgrade now. Upgrade pricing is shown below. Click here to sign on to your account to purchase an upgrade or additional product.

At FamilyTreeDNA, by taking advantage of autosomal plus Y-DNA and mitochondrial DNA, you will get to know your ancestors in ways not possible elsewhere. You can even identify or track them using your myOrigins painted ethnicity segments.

FamilyTreeDNA divides your Family Finder matches maternal and paternally for you if you create or upload a tree and link known testers. How cool is this?!!!

MyHeritage

The MyHeritage DNA test is on sale for $36, the best autosomal test price I’ve ever seen anyplace.

MyHeritage has a significant European presence and I find European matches at MyHeritage that aren’t anyplace else. MyHeritage utilizes user trees and DNA matches to construct Theories of Family Relativity that shows how you and your matches may be related.

Remember, you can upload the raw data file from the MyHeritage DNA test to both FamilyTreeDNA and GEDmatch for free.

Free shipping on 2 kits or more.

This sale ends at the end-of-day on Black Friday.

You can combine your DNA test with a MyHeritage records subscription with a free trial, here.

Ancestry

The AncestryDNA test is $59, here. With Ancestry’s super-size DNA database, you’re sure to get lots of matches and hints via ThruLines.

You can get free shipping if you’re an Amazon Prime member.

If you order an AncestryDNA test, you can upload the raw DNA file to FamilyTreeDNA, MyHeritage and GEDmatch for free. Unfortunately, Ancestry does not accept uploads from other vendors.

23andMe

The 23andMe Ancestry + Traits DNA test is $79, here. 23andMe is well known for its Ancestry Composition (ethnicity) results and one-of-a-kind genetic tree.

The 23andMe Ancestry + Traits + Health test is now $99, here.

You can get free shipping if you’re an Amazon Prime member.

If you order either of the 23andMe tests, you can upload the raw data file to FamilyTreeDNA, MyHeritage, and GEDmatch for free. Unfortunately, 23andMe does not accept uploads from other vendors.

Can’t Wait!!

This is always my favorite time of the year because I know that beginning soon, we will all be receiving lots of new matches from people who purchased or received DNA tests during the holiday season.

  • What can you do to enhance your genealogy?
  • Have you ordered Y and mitochondrial DNA tests for yourself and people who carry the Y and mitochondrial DNA of your ancestors?
  • Are you in all of the autosomal databases?
  • Who are you ordering tests for?

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Share the Love!

You’re always welcome to forward articles or links to friends and share on social media.

If you haven’t already subscribed (it’s free,) you can receive an email whenever I publish by clicking the “follow” button on the main blog page, here.

You Can Help Keep This Blog Free

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Uploads

Genealogy Products and Services

My Book

Genealogy Books

Genealogy Research

DNA: In Search of…Full and Half-Siblings

This is the fifth article in our series of articles about searching for unknown close family members, specifically; parents, grandparents, or siblings. However, these same techniques can be applied by genealogists to identify ancestors further back in time as well.

Please note that if a family member has tested and you do NOT see their results, ask them to verify that they have chosen to allow matching and for other people to view them in their match list. That process varies at different vendors.

You can also ask if they can see you in their results.

All Parties Need to Test

Searching for unknown siblings isn’t exactly searching, because to find them, they, themselves, or their descendant(s) must have taken a DNA test at the same vendor where you tested or uploaded a DNA file.

You may know through any variety of methods that they exist, or might exist, but if they don’t take a DNA test, you can’t find them using DNA. This might sound obvious, but I see people commenting and not realizing that the other sibling(s) must test too – and they may not have.

My first questions when someone comments in this vein are:

  1. Whether or not they are positive their sibling actually tested, meaning actually sent the test in to the vendor, and it was received by the testing company. You’d be surprised how many tests are living in permanent residence on someone’s countertop until it gets pushed into the drawer and forgotten about.
  2. If the person has confirmed that their sibling has results posted. They may have returned their test, but the results aren’t ready yet or there was a problem.
  3. AND that both people have authorized matching and sharing of results. Don’t hesitate to reach out to your vendor’s customer care if you need help with this.

Sibling Scenarios

The most common sibling scenarios are when one of two things happens:

  • A known sibling tests, only to discover that they don’t match you in the full sibling range, or not at all, when you expected they would
  • You discover a surprise match in the full or half-sibling range

Let’s talk about these scenarios and how to determine:

  • If someone is a sibling
  • If they are a full or half-sibling
  • If a half-sibling, if they descend from your mother or father

As with everything else genetic, we’ll be gathering and analyzing different pieces of evidence along the way.

Full and Half-Siblings

Just to make sure we are all on the same page:

  • A full sibling is someone who shares both parents with you.
  • A half-sibling is someone who shares one parent with you, but not the other parent.
  • A step-sibling is someone who shares no biological parents with you. This situation occurs when your parent marries their parent, after you are both born, and their parent becomes your step-parent. You share neither of your biological parents with a step-sibling, so you share no DNA and will not show up on each other’s match lists.
  • A three-quarters sibling is someone with whom you share one parent, but two siblings are the other parent. For example, you share the same mother, but one brother fathered you, and your father’s brother fathered your sibling. Yes, this can get very messy and is almost impossible for a non-professional to sort through, if even then. (This is not a solicitation. I do not take private clients.) We will not be addressing this situation specifically.

Caution

With any search for unknown relatives, you have no way of knowing what you will find.

In one’s mind, there are happy reunions, but you may experience something entirely different. Humans are human. Their stories are not always happy or rosy. They may have made mistakes they regret. Or they may have no regrets about anything.

Your sibling may not know about you or the situation under which you, or they, were born. Some women were victims of assault and violence, which is both humiliating and embarrassing. I wrote about difficult situations, here.

Your sibling or close family member may not be receptive to either you, your message, or even your existence. Just be prepared, because the seeking journey may not be pain-free for you or others, and may not culminate with or include happy reunions.

On the other hand, it may.

Please step back and ponder a bit about the journey you are about to undertake and the possible people that may be affected, and how. This box, once opened, cannot be closed again. Be sure you are prepared.

On the other hand, sometimes that box lid pops off, and the information simply falls in your lap one day when you open your match list, and you find yourself sitting there, in shock, staring at a match, trying to figure out what it all means.

Congratulations, You Have a Sibling!

This might not be exactly what runs through your mind when you see that you have a very close match that you weren’t expecting.

The first two things I recommend when making this sort of discovery, after a few deep breaths, a walk, and a cup of tea, are:

  • Viewing what the vendor says
  • Using the DNAPainter Shared cM Relationship Chart

Let’s start with DNAPainter.

DNAPainter

DNAPainter provides a relationship chart, here, based on the values from the Shared cM Project.

You can either enter a cM amount or a percentage of shared DNA. I prefer the cM amount, but it doesn’t really matter.

I’ll enter 2241 cM from a known half-sibling match. To enter a percent, click on the green “enter %.”

As you can see, statistically speaking, this person is slightly more likely to be a half-sibling than they are to be a full sibling. In reality, they could be either.

Looking at the chart below, DNAPainter highlights the possible relationships from the perspective of “Self.”

The average of all the self-reported relationships is shown, on top, so 2613 for a full sibling. The range is shown below, so 1613-3488 for a full sibling.

In this case, there are several possibilities for two people who share 2241 cM of DNA.

I happen to know that these two people are half-siblings, but if I didn’t, it would be impossible to tell from this information alone.

The cM range for full siblings is 1613-3488, and the cM range for half-siblings is 1160-2436.

  • The lower part of the matching range, from 1160-1613 cM is only found in half-siblings.
  • The portion of the range from 1613-2436 cM can be either half or full siblings.
  • The upper part of the range, from 2436-3488 cM is only found in full siblings.

If your results fall into the center portion of the range, you’re going to need to utilize other tools. Fortunately, we have several.

If you’ve discovered something unexpected, you’ll want to verify using these tools, regardless. Use every tool available. Ranges are not foolproof, and the upper and lower 10% of the responses were removed as outliers. You can read more about the shared cM Project, here and here.

Furthermore, people may be reporting some half-sibling relationships as full sibling relationships, because they don’t expect to be half-siblings, so the ranges may be somewhat “off.”

Relationship Probability Calculator

Third-party matching database, GEDmatch, provides a Relationship Probability Calculator tool that is based on statistical probability methods without compiled user input. Both tools are free, and while I haven’t compared every value, both seem to be reasonably accurate, although they do vary somewhat, especially at the outer ends of the ranges.

When dealing with sibling matches, if you are in all four databases, GEDmatch is a secondary resource, but I will include GEDmatch when they have a unique tool as well as in the summary table. Some of your matches may be willing to upload to GEDmatch if the vendor where you match doesn’t provide everything you need and GEDmatch has a supplemental offering.

Next, let’s look at what the vendors say about sibling matches.

Vendors

Each of the major vendors reports sibling relationships in a slightly different way.

Sibling Matches at Ancestry

Ancestry reports sibling relationships as Sister or Brother, but they don’t say half or full.

If you click on the cM portion of the link, you’ll see additional detail, below

Ancestry tells you that the possible relationships are 100% “Sibling.” The only way to discern the difference between full and half is by what’s next.

If the ONLY relationship shown is Sibling at 100%, that can be interpreted to mean this person is a full sibling, and that a half-sibling or other relationship is NOT a possibility.

Ancestry never stipulates full or half.

The following relationship is a half-sibling at Ancestry.

Ancestry identifies that possible range of relationships as “Close Family to First Cousin” because of the overlaps we saw in the DNAPainter chart.

Clicking through shows that there is a range of possible relationships, and Ancestry is 100% sure the relationship is one of those.

DNAPainter agrees with Ancestry except includes the full-sibling relationship as a possibility for 1826 cM.

Sibling Matches at 23andMe

23andMe does identify full versus half-siblings.

DNAPainter disagrees with 23andMe and claims that anyone who shares 46.2% of their DNA is a parent/child.

However, look at the fine print. 23andMe counts differently than any of the other vendors, and DNAPainter relies on the Shared cM Project, which relies on testers entering known relationship matching information. Therefore, at any other vendor, DNAPainter is probably exactly right.

Before we understand how 23andMe counts, we need to understand about half versus fully identical segments.

To determine half or full siblings, 23andMe compares two things:

  1. The amount of shared matching DNA between two people
  2. Fully Identical Regions (FIR) of DNA compared to Half Identical Regions (HIR) of DNA to determine if any of your DNA is fully identical, meaning some pieces of you and your sibling’s DNA is exactly the same on both your maternal and paternal chromosomes.

Here’s an example on any chromosome – I’ve randomly selected chromosome 12. Which chromosome doesn’t matter, except for the X, which is different.

Your match isn’t broken out by maternal and paternal sides. You would simply see, on the chromosome browser, that you and your sibling match at these locations, above.

In reality, though, you have two copies of each chromosome, one from Mom and one from Dad, and so does your sibling.

In this example, Mom’s chromosome is visualized on top, and Dad’s is on the bottom, below, but as a tester, you don’t know that. All you know is that you match your sibling on all of those blue areas, above.

However, what’s actually happening in this example is that you are matching your sibling on parts of your mother’s chromosome and parts of your father’s chromosome, shown above as green areas

23andMe looks at both copies of your chromosome, the one you inherited from Mom, on top, and Dad, on the bottom, to see if you match your sibling on BOTH your mother’s and your father’s chromosomes in that location.

I’ve boxed the green matching areas in purple where you match your sibling fully, on both parents’ chromosomes.

If you and your sibling share both parents, you will share significant amounts of the same DNA on both copies of the same chromosomes, meaning maternal and paternal. In other words, full siblings share some purple fully identical regions (FIR) of DNA with each other, while half-siblings do not (unless they are also otherwise related) because half-siblings only share one parent with each other. Their DNA can’t be fully identical because they have a different parent that contributed the other copy of their chromosome.

Total Shared DNA Fully Identical DNA from Both Parents
Full Siblings ~50% ~25%
Half Siblings ~25% 0
  • Full siblings are expected to share about 50% of the same DNA. In other words, their DNA will match at that location. That’s all the green boxed locations, above.
  • Full siblings are expected to share about 25% of the same DNA from BOTH parents at the same location on BOTH copies of their chromosomes. These are fully identical regions and are boxed in purple, above.

You’ll find fully identical segments about 25% of the time in full siblings, but you won’t find fully identical segments in half-siblings. Please note that there are exceptions for ¾ siblings and endogamous populations.

You can view each match at 23andMe to see if you have any completely identical regions, shown in dark purple in the top comparison of full siblings. Half siblings are shown in the second example, with less total matching DNA and no FIR or completely identical regions.

Please note that your matching amount of DNA will probably be higher at 23andMe than at other companies because:

  • 23andMe includes the X chromosome in the match totals
  • 23andMe counts fully identical matching regions twice. For full siblings, that’s an additional 25%

Therefore, a full sibling with an X match will have a higher total cM at 23andMe than the same siblings elsewhere because not only is the X added into the total, the FIR match region is added a second time too.

Fully Identical Regions (FIR) and Half Identical Regions (HIR) at GEDmatch

At GEDMatch, you can compare two people to each other, with an option to display the matching information and a painted graphic for each chromosome that includes FIR and HIR.

If you need to know if you and a match share fully identical regions and you haven’t tested at 23andMe, you can both upload your DNA data file to GEDmatch and use their One to One Autosomal DNA Comparison.

On the following page, simply enter both kit numbers and accept the defaults, making sure you have selected one of the graphics options.

While GEDmatch doesn’t specifically tell you whether someone is a full or half sibling, you can garner additional information about the relationship based on the graphic at GEDmatch.

GEDMatch shows both half and fully identical regions.

The above match is between two full siblings using a 7 cM threshold. The blue on the bottom bar indicates a match of 7 cM or larger. Black means no match.

The green regions in the top bar indicate places where these two people carry the same DNA on both copies of their chromosome 1. This means that both people inherited the same DNA from BOTH parents on the green segments.

In the yellow regions, the siblings inherited the same DNA from ONE parent, but different DNA in that region from the other parent. They do match each other, just on one of their chromosomes, not both.

Without a tool like this to differentiate between HIR and FIR, you can’t tell if you’re matching someone on one copy of your chromosome, or on both copies.

In the areas marked with red on top, which corresponds to the black on the bottom band, these two siblings don’t match each other because they inherited different DNA from both parents in that region. The yellow in that region is too scattered to be significant.

Full siblings generally share a significant amount of FIR, or fully identical regions of DNA – about 25%.

Half siblings will share NO significant amount of FIR, although some will be FIR on very small, scattered green segments simply by chance, as you can see in the example, below.

This half-sibling match shares no segments large enough to be a match (7 cM) in the black section. In the blue matching section, only a few small green fragments of DNA match fully, which, based on the rest of that matching segment, must be identical by chance or misreads. There are no significant contiguous segments of fully identical DNA.

When dealing with full or half-siblings, you’re not interested in small, scattered segments of fully identical regions, like those green snippets on chromosome 6, but in large contiguous sections of matching DNA like the chromosome 1 example.

GEDmatch can help when you match when a vendor does not provide FIR/HIR information, and you need additional assistance.

Next, let’s look at full and half-siblings at FamilyTreeDNA

Sibling Matches at FamilyTreeDNA

FamilyTreeDNA does identify full siblings.

Relationships other than full siblings are indicated by a range. The two individuals below are both half-sibling matches to the tester.

The full range when mousing over the relationship ranges is shown below.

DNAPainter agrees except also gives full siblings as an option for the two half-siblings.

FamilyTreeDNA also tells you if you have an X match and the size of your X match.

We will talk about X matching in a minute, which, when dealing with sibling identification, can turn out to be very important.

Sibling Matches at MyHeritage

MyHeritage indicates brother or sister for full siblings

MyHeritage provides other “Estimated relationships” for matches too small to be full siblings.

DNAPainter’s chart agrees with this classification, except adds additional relationship possibilities.

Be sure to review all of the information provided by each vendor for close relationships.

View Close Known Relationships

The next easiest step to take is to compare your full or half-sibling match to known close family members from your maternal and paternal sides, respectively. The closer the family members, the better.

It’s often not possible to determine if someone is a half sibling or a full sibling by centiMorgans (cMs) alone, especially if you’re searching for unknown family members.

Let’s start with the simplest situation first.

Let’s say both of your parents have tested, and of course, you match both of them as parents.

Your new “very close match” is in the sibling range.

The first thing to do at each vendor is to utilize that vendor’s shared matches tool and see whether your new match matches one parent, or both.

Here’s an example.

Close Relationships at FamilyTreeDNA

This person has a full sibling match, but let’s say they don’t know who this is and wants to see if their new sibling matches one or both of their parents.

Select the match by checking the box to the left of the match name, then click on the little two-person icon at far right, which shows “In Common” matches

You can see on the resulting shared match list that both of the tester’s parents are shown on the shared match list.

Now let’s make this a little more difficult.

No Parents, No Problem

Let’s say neither of your parents has tested.

If you know who your family is and can identify your matches, you can see if the sibling you match matches other close relatives on both or either side of your family.

You’ll want to view shared matches with your closest known match on both sides of your tree, beginning with the closest first. Aunts, uncles, first cousins, etc.

You will match all of your family members through second cousins, and 90% of your third cousins. You can view additional relationship percentages in the article, How Much of Them is in You?.

I recommend, for this matching purpose, to utilize 2nd cousins and closer. That way you know for sure if you don’t share them as a match with your sibling, it’s because the sibling is not related on that side of the family, not because they simply don’t share any DNA due to their distance.

In this example, you have three sibling matches. Based on your and their matches to the same known first and second cousins, you can see that:

  • Sibling 1 is your full sibling, because you both match the same maternal and paternal first and second cousins
  • Sibling 2 is your paternal half-sibling because you both match paternal second cousins and closer, but not maternal cousins.
  • Sibling 3 is your maternal half-sibling because you both match maternal second cousins and closer, but not paternal cousins.

Close Relationships at Ancestry

Neither of my parents have tested, but my first cousin on my mother’s side has. Let’s say I have a suspected sibling or half-sibling match, so I click on the match’s name, then on Shared Matches.

Sure enough, my new match also matches my first cousin that I’ve labeled as “on my mother’s side.”

If my new match in the sibling range also matches my second cousins or closer on my father’s side, the new match is a full sibling, not a half-sibling.

Close Relationships at MyHeritage

Comparing my closest match provided a real surprise. I wonder if I’ve found a half-sibling to my mother.

Now, THIS is interesting.

Hmmm. More research is needed, beginning with the age of my match. MyHeritage provides ages if the MyHeritage member authorizes that information to be shared.

Close Relationships at 23andMe

Under DNA Relatives, click on your suspected sibling match, then scroll down and select “Find Relatives in Common.”

The Relatives in Common list shows people that match both of you.

The first common match is very close and a similar relationship to my closest match on my father’s side. This would be expected of a sibling. I have no common matches with this match to anyone on my mother’s side, so they are only related on my father’s side. Therefore they are a paternal half-sibling, not a full sibling.

More Tools Are Available

Hopefully, by now, you’ve been able to determine if your mystery match is a sibling, and if so, if they are a half or full sibling, and through which parent.

We have some additional tools that are relevant and can be very informative in some circumstances. I suggest utilizing these tools, even if you think you know the answer.

In this type of situation, there’s no such thing as too much information.

X Matching

X matching, or lack thereof, may help you determine how you are related to someone.

There are two types of autosomal DNA. The X chromosome versus chromosomes 1-22. The X chromosome (number 23) has a unique inheritance path that distinguishes it from your other chromosomes.

The X chromosome inheritance path also differs between men and women.

Here’s my pedigree chart in fan form, highlighting the ancestors who may have contributed a portion of their X chromosome to me. In the closest generation, this shows that I inherited an X chromosome from both of my parents, and who in each of their lines could have contributed an X to them.

The white or uncolored positions, meaning ancestors, cannot contribute any portion of an X chromosome to me based on how the X chromosome is inherited.

You’ll notice that my father inherited none of his X chromosome from any of his paternal ancestors, so of course, I can’t inherit what he didn’t inherit. There are a very limited number of ancestors on my father’s side whom I can inherit any portion of an X chromosome from.

Men receive their Y chromosome from their fathers, so men ONLY receive an X chromosome from their mother.

Therefore, men MUST pass their mother’s X chromosome on to their female offspring because they don’t have any other copy of the X chromosome to pass on.

Men pass no X chromosome to sons.

We don’t need to worry about a full fan chart when dealing with siblings and half-siblings.

We only need to be concerned with the testers plus one generation (parents) when utilizing the X chromosome in sibling situations.

These two female Disney Princesses, above, are full siblings, and both inherited an X chromosome from BOTH their mother and father. However, their father only has one X (red) chromosome to give them, so the two females MUST match on the entire red X chromosome from their father.

Their mother has two X chromosomes, green and black, to contribute – one from each of her parents.

The full siblings, Melody, and Cinderella:

  • May have inherited some portion of the same green and black X chromosomes from their mother, so they are partial matches on their mother’s X chromosome.
  • May have inherited the exact same full X chromosome from their mother (both inherited the entire green or both inherited the entire black), so they match fully on their mother’s X chromosome.
  • May have inherited the opposite X from different maternal grandparents. One inherited the entire green X and one inherited the entire black X, so they don’t match on their mother’s X chromosome.

Now, let’s look at Cinderella, who matches Henry.

This female and male full sibling match can’t share an X chromosome on the father’s side, because the male’s father doesn’t contribute an X chromosome to him. The son, Henry, inherited a Y chromosome instead from his father, which is what made them males.

Therefore, if a male and female match on the X chromosome, it MUST be through HIS mother, but could be through either of her parents. In a sibling situation, an X match between a male and female always indicates the mother.

In the example above, the two people share both of their mother’s X chromosomes, so are definitely (at least) maternally related. They could be full siblings, but we can’t determine that by the X chromosome in this situation, with males.

However, if the male matches the female on HER father’s X chromosome, there a different message, example below.

You can see that the male is related to the female on her father’s side, where she inherited the entire magenta X chromosome. The male inherited a portion of the magenta X chromosome from his mother, so these two people do have an X match. However, he matches on his mother’s side, and she matches on her father’s side, so that’s clearly not the same parent.

  • These people CAN NOT be full siblings because they don’t match on HER mother’s side too, which would also be his mother’s side if they were full siblings.
  • They cannot be maternal half-siblings because their X DNA only matches on her father’s side, but they wouldn’t know that unless she knew which side was which based on share matches.
  • They cannot be paternal half-siblings because he does not have an X chromosome from his father.

They could, however, be uncle/aunt-niece/nephew or first cousins on his mother’s side and her father’s side. (Yes, you’re definitely going to have to read this again if you ever need male-female X matching.)

Now, let’s look at X chromosome matching between two males. It’s a lot less complicated and much more succinct.

Neither male has inherited an X chromosome from their father, so if two males DO match on the X, it MUST be through their mother. In terms of siblings, this would mean they share the same mother.

However, there is one slight twist. In the above example, you can see that the men inherited a different proportion of the green and black X chromosomes from their common mother. However, it is possible that the mother could contribute her entire green X chromosome to one son, Justin in this example, and her entire black X chromosome to Henry.

Therefore, even though Henry and Justin DO share a mother, their X chromosome would NOT match in this scenario. This is rare but does occasionally happen.

Based on the above examples, the X chromosome may be relevant in the identification of full or half siblings based on the sexes of the two people who otherwise match at a level indicating a full or half-sibling relationship.

Here’s a summary chart for sibling X matching.

X Match Female Male
Female Will match on shared father’s full X chromosome, mother’s X is the same rules as chromosomes 1-22 Match through male’s mother, but either of female’s parents. If the X match is not through the female’s mother, they are not full siblings nor maternal half-siblings. They cannot have an X match through the male’s father. They are either full or half-siblings through their mother if they match on both of their mother’s side. If they match on his mother’s side, and her father’s side, they are not siblings but could be otherwise closely related.
Male Match through male’s mother, but either of female’s parents. If the X match is not through the female’s mother, they are not full siblings nor maternal half-siblings. They cannot have an X match through the male’s father. They are either full or half-siblings through their mother if they match on both or their mother’s side. If they match on his mother’s side, and her father’s side, they are not siblings but could be otherwise closely related. Both males are related on their mother’s side – either full or half-siblings.

Here’s the information presented in a different way.

DOES match X summary:

  • If a male DOES match a female on the X, he IS related to her through HIS mother’s side, but could match her on her mother or father’s side. If their match is not through her mother, then they are not full siblings nor maternal half-siblings. They cannot match through his father, so they cannot be paternal half-siblings.
  • If a female DOES match a female on the X, they could be related on either side and could be full or half-siblings.
  • If a male DOES match a male on the X, they ARE both related through their mother. They may also be related on their father’s side, but the X does not inform us of that.

Does NOT match X summary:

  • If a male does NOT match a female on the X, they are NOT related through HIS mother and are neither full siblings nor maternal half-siblings. Since a male does not have an X chromosome from his father, they cannot be paternal half-siblings based on an X match.
  • If a male does NOT match a male, they do NOT share a mother.
  • If a female does NOT match another female on the X, they are NOT full siblings and are NOT half-siblings on their paternal side. Their father only has one X chromosome, and he would have given the same X to both daughters.

Of the four autosomal vendors, only 23andMe and FamilyTreeDNA report X chromosome results and matching, although the other two vendors, MyHeritage and Ancestry, include the X in their DNA download file so you can find X matches with those files at either FamilyTreeDNA or GEDMatch if your match has or will upload their file to either of those vendors. I wrote step-by-step detailed download/upload instructions, here.

X Matching at FamilyTreeDNA

In this example from FamilyTreeDNA, the female tester has discovered two half-sibling matches, both through her father. In the first scenario, she matches a female on the full X chromosome (181 cM). She and her half-sibling MUST share their father’s entire X chromosome because he only had one X, from his mother, to contribute to both of his daughters.

In the second match to a male half-sibling, our female tester shares NO X match because her father did not contribute an X chromosome to his son.

If we didn’t know which parents these half-sibling matches were through, we can infer from the X matching alone that the male is probably NOT through the mother.

Then by comparing shared matches with each sibling, Advanced Matches, or viewing the match Matrix, we can determine if the siblings match each other and are from the same or different sides of the family.

Under Additional Tests and Tools, Advanced Matching, FamilyTreeDNA provides an additional tool that can show only X matches combined with relationships.

Of course, you’ll need to view shared matches to see which people match the mother and/or match the father.

To see who matches each other, you’ll need to use the Matrix tool.

At FamilyTreeDNA, the Matrix, located under Autosomal DNA Results and Tools, allows you to select your matches to see if they also match each other. If you have known half-siblings, or close relatives, this is another way to view relationships.

Here’s an example using my father and two paternal half-siblings. We can see that the half-siblings also match each other, so they are (at least) half-siblings on the paternal side too.

If they also matched my mother, we would be full siblings, of course.

Next, let’s use Y DNA and mitochondrial DNA.

Y DNA and Mitochondrial DNA

In addition to autosomal DNA, we can utilize Y DNA and mitochondrial DNA (mtDNA) in some cases to identify siblings or to narrow or eliminate relationship possibilities.

Given that Y DNA and mitochondrial DNA both have distinctive inheritance paths, full and half-siblings will, or will not, match under various circumstances.

Y DNA

Y DNA is passed intact from father to son, meaning it’s not admixed with any of the mother’s DNA. Daughters do not inherit Y DNA from their father, so Y DNA is only useful for male-to-male comparisons.

Two types of Y DNA are used for genealogy, STR markers for matching, and haplogroups, and both are equally powerful in slightly different ways.

Y DNA at FamilyTreeDNA

Men can order either 37 or 111 STR marker tests, or the BIg Y which provides more than 700 markers and more. FamilyTreeDNA is the only one of the vendors to offer Y DNA testing that includes STR markers and matching between men.

Men who order these tests will be compared for matching on either 37, 111 or 700 STR markers in addition to SNP markers used for haplogroup identification and assignment.

Fathers will certainly match their sons, and paternal line brothers will match each other, but they will also match people more distantly related.

However, if two men are NOT either full or half siblings on the paternal side, they won’t match at 111 markers.

If two men DON’T match, especially at high marker levels, they likely aren’t siblings. The word “likely” is in there because, very occasionally, a large deletion occurs that prevents STR matching, especially at lower levels.

Additionally, men who take the 37 or 111 marker test also receive an estimated haplogroup at a high level for free, without any additional testing.

However, if men take the Big Y-700 test, they not only will (or won’t) match on up to 700 STR markers, they will also receive a VERY refined haplogroup via SNP marker testing that is often even more sensitive in terms of matching than STR markers. Between these two types of markers, Y DNA testing can place men very granularly in relation to other men.

Men can match in two ways on Y DNA, and the results are very enlightening.

If two men match on BOTH their most refined haplogroup (Big Y test) AND STR markers, they could certainly be siblings or father/son. They could also be related on the same line for another reason, such as known or unknown cousins or closer relationships like uncle/nephew. Of course, Y DNA, in addition to autosomal matching, is a powerful combination.

Conversely, if two men don’t have a similar or close haplogroup, they are not a father and son or paternal line siblings.

FamilyTreeDNA offers both inexpensive entry-level testing (37 and 111 markers) and highly refined advanced testing of most of the Y chromosome (Big Y-700), so haplogroup assignments can vary widely based on the test you take. This makes haplogroup matching and interpretation a bit more complex.

For example, haplogroups R-M269 and I-BY14000 are not related in thousands of years. One is haplogroup R, and one is haplogroup I – completely different branches of the Y DNA tree. These two men won’t match on STR markers or their haplogroup.

However, because FamilyTreeDNA provides over 50,000 different haplogroups, or tree branches, for Big Y testers, and they provide VERY granular matching, two father/son or sibling males who have BOTH tested at the Big Y-700 level will have either the exact same haplogroup, or at most, one branch difference on the tree if a mutation occurred between father and son.

If both men have NOT tested at the Big Y-700 level, their haplogroups will be on the same branch. For example, a man who has only taken a 37/111 marker STR test may be estimated at R-M269, which is certainly accurate as far as it goes.

His sibling who has taken a Big Y test will be many branches further downstream on the tree – but on the same large haplogroup R-M269 branch. It’s essential to pay attention to which tests a Y DNA match has taken when analyzing the match.

The beauty of the two kinds of tests is that even if one haplogroup is very general due to no Big Y test, their STR markers should still match. It’s just that sometimes this means that one hand is tied behind your back.

Y DNA matching alone can eliminate the possibility of a direct paternal line connection, but it cannot prove siblingship or paternity alone – not without additional information.

The Advanced Matching tool will provide a list of matches in all categories selected – in this case, both the 111 markers and the Family Finder test. You can see that one of these men is the father of the tester, and one is the full sibling.

You can view haplogroup assignments on the public Y DNA tree, here. I wrote about using the public tree, here.

In addition, recently, FamilyTreeDNA launched the new Y DNA Discover tool, which explains more about haplogroups, including their ages and other fun facts like migration paths along with notable and ancient connections. I wrote about using the Discover tool, here.

Y DNA at 23andMe

Testers receive a base haplogroup with their autosomal test. 23andMe tests a limited number of Y DNA SNP locations, but they don’t test many, and they don’t test STR markers, so there is no Y DNA matching and no refined haplogroups.

You can view the haplogroups of your matches. If your male sibling match does NOT share the same haplogroup, the two men are not paternal line siblings. If two men DO share the same haplogroup, they MIGHT be paternal siblings. They also might not.

Again, autosomal close matching plus haplogroup comparisons include or exclude paternal side siblings for males.

Paternal side siblings at 23andMe share the same haplogroup, but so do many other people. These two men could be siblings. The haplogroups don’t exclude that possibility. If the haplogroups were different, that would exclude being either full or paternal half-siblings.

Men can also compare their mitochondrial DNA to eliminate a maternal relationship.

These men are not full siblings or maternal half-siblings. We know, unquestionably, because their mitochondrial haplogroups don’t match.

23andMe also constructs a genetic tree, but often struggles with close relative placement, especially when half-relationships are involved. I do not recommend relying on the genetic tree in this circumstance.

Mitochondrial DNA

Mitochondrial DNA is passed from mothers to all of their children, but only females pass it on. If two people, males or females, don’t match on their mitochondrial DNA test, with a couple of possible exceptions, they are NOT full siblings, and they are NOT maternal half-siblings.

Mitochondrial DNA at 23andMe

23andMe provides limited, base mitochondrial haplogroups, but no matching. If two people don’t have the same haplogroup at 23andMe, they aren’t full or maternal siblings, as illustrated above.

Mitochondrial DNA at FamilyTreeDNA

FamilyTreeDNA provides both mitochondrial matching AND a much more refined haplogroup. The full sequence test (mtFull), the only version sold today, is essential for reliable comparisons.

Full siblings or maternal half-siblings will always share the same haplogroup, regardless of their sex.

Generally, a full sibling or maternal half-sibling match will match exactly at the full mitochondrial sequence (FMS) level with a genetic distance of zero, meaning fully matching and no mismatching mutations.

There are rare instances where maternal siblings or even mothers and children do not match exactly, meaning they have a genetic distance of greater than 0, because of a mutation called a heteroplasmy.

I wrote about heteroplasmies, here.

Like Y DNA, mitochondrial DNA cannot identify a sibling or parental relationship without additional evidence, but it can exclude one, and it can also provide much-needed evidence in conjunction with autosomal matching. The great news is that unlike Y DNA, everyone has mitochondrial DNA and it comes directly from their mother.

Once again, FamilyTreeDNA’s Advanced Matching tool provides a list of people who match you on both your mitochondrial DNA test and the Family Finder autosomal test, including transfers/uploads, and provides a relationship.

You can see that our tester matches both a full sibling and their mother. Of course, a parent/child match could mean that our tester is a female and one of her children, of either sex, has tested.

Below is an example of a parent-child match that has experienced a heteroplasmy.

Based on the comparison of both the mitochondrial DNA test, plus the autosomal Family Finder test, you can verify that this is a close family relationship.

You can also eliminate potential relationships based on the mitochondrial DNA inheritance path. The mitochondrial DNA of full siblings and maternal half-siblings will always match at the full sequence and haplogroup level, and paternal half-siblings will never match. If paternal half-siblings do match, it’s happenstance or because of a different reason.

Sibling Summary and Checklist

I’ve created a quick reference checklist for you to use when attempting to determine whether or not a match is a sibling, and, if so, whether they are half or full siblings. Of course, these tools are in addition to the DNAPainter Shared cM Tool and GEDmatch’s Relationship Predictor Calculator.

FamilyTreeDNA Ancestry 23andMe MyHeritage GEDmatch
Matching Yes Yes Yes Yes Yes
Shared Matches Yes – In Common With Yes – Shared Matches Yes – Relatives in Common Yes – Review DNA Match Yes – People who match both or 1 of 2 kits
Relationship Between Shared Matches No No No Yes, under shared match No
Matches Match Each Other* Yes, Matrix No Yes, under “View DNA details,” then, “compare with more relatives” Partly, through triangulation Yes, can match any kits
Full Siblings Yes Sibling, implies full Yes Brother, Sister, means full No
Half Siblings Sibling, Uncle/Aunt-Niece/Nephew, Grandparent-Grandchild Close Family – 1C Yes Half sibling, aunt/uncle-niece-nephew No
Fully Identical Regions (FIR) No No Yes No Yes
Half Identical Regions (HIR) No No Yes No Yes
X matching Yes No Yes No Yes
Unusual Reporting or Anomalies No No, Timber is not used on close relationships X match added into total, FIR added twice No Matching amount can vary from vendors
Y DNA Yes, STRs, refined haplogroups, matching No High-level haplogroup only, no matching No No, only if tester enters haplogroup manually
Mitochondrial DNA Yes, full sequence, matching, refined haplogroup No High-level haplogroup only, no matching No No, only if tester enters haplogroup manually
Combined Tools (Autosomal, X, Y, mtDNA) Yes No No No No

*Autoclusters through Genetic Affairs show cluster relationships of matches to the tester and to each other, but not all matches are included, including close matches. While this is a great tool, it’s not relevant for determining close and sibling relationships. See the article, AutoClustering by Genetic Affairs, here.

Additional Resources

Some of you may be wondering how endogamy affects sibling numbers.

Endogamy makes almost everything a little more complex. I wrote about endogamy and various ways to determine if you have an endogamous heritage, here.

Please note that half-siblings with high cM matches also fall into the range of full siblings (1613-3488), with or without endogamy. This may be, but is not always, especially pronounced in endogamous groups.

As another resource, I wrote an earlier article, Full or Half Siblings, here, that includes some different examples.

Strategy

You have a lot of quills in your quiver now, and I wish you the best if you’re trying to unravel a siblingship mystery.

You may not know who your biological family is, or maybe your sibling doesn’t know who their family is, but perhaps your close relatives know who their family is and can help. Remember, the situation that has revealed itself may be a shock to everyone involved.

Above all, be kind and take things slow. If your unexpected sibling match becomes frightened or overwhelmed, they may simply check out and either delete their DNA results altogether or block you. They may have that reaction before you have a chance to do anything.

Because of that possibility, I recommend performing your analysis quickly, along with taking relevant screenshots before reaching out so you will at least have that much information to work with, just in case things go belly up.

When you’re ready to make contact, I suggest beginning by sending a friendly, short, message saying that you’ve noticed that you have a close match (don’t say sibling) and asking what they know about their family genealogy – maybe ask who their grandparents are or if they have family living in the area where you live. I recommend including a little bit of information about yourself, such as where you were born and are from.

I also refrain from using the word adoption (or similar) in the beginning or giving too much detailed information, because it sometimes frightens people, especially if they know or discover that there’s a painful or embarrassing family situation.

And, please, never, ever assume the worst of anyone or their motives. They may be sitting at their keyboard with the same shocked look on their face as you – especially if they have, or had, no idea. They may need space and time to reach a place of acceptance. There’s just nothing more emotionally boat-capsizing in your life than discovering intimate and personal details about your parents, one or both, especially if that discovery is disappointing and image-altering.

Or, conversely, your sibling may have been hoping and waiting just for you!

Take a deep breath and let me know how it goes!

Please feel free to share this article with anyone who could benefit.

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DNA: In Search of…Signs of Endogamy

This is the fourth in our series of articles about searching for unknown close family members, specifically; parents, grandparents, or siblings. However, these same techniques can be applied by genealogists to ancestors further back in time as well.

In this article, we discuss endogamy – how to determine if you have it, from what population, and how to follow the road signs.

After introductions, we will be covering the following topics:

  • Pedigree collapse and endogamy
  • Endogamous groups
  • The challenge(s) of endogamy
  • Endogamy and unknown close relatives (parents, grandparents)
  • Ethnicity and Populations
  • Matches
  • AutoClusters
  • Endogamous Relationships
  • Endogamous DNA Segments
  • “Are Your Parents Related?” Tool
  • Surnames
  • Projects
  • Locations
  • Y DNA, Mitochondrial DNA, and Endogamy
  • Endogamy Tools Summary Tables
    • Summary of Endogamy Tools by Vendor
    • Summary of Endogamous Populations Identified by Each Tool
    • Summary of Tools to Assist People Seeking Unknown Parents and Grandparents

What Is Endogamy and Why Does It Matter?

Endogamy occurs when a group or population of people intermarry among themselves for an extended period of time, without the introduction of many or any people from outside of that population.

The effect of this continual intermarriage is that the founders’ DNA simply gets passed around and around, eventually in small segments.

That happens because there is no “other” DNA to draw from within the population. Knowing or determining that you have endogamy helps make sense of DNA matching patterns, and those patterns can lead you to unknown relatives, both close and distant.

This Article

This article serves two purposes.

  • This article is educational and relevant for all researchers. We discuss endogamy using multiple tools and examples from known endogamous people and populations.
  • In order to be able to discern endogamy when we don’t know who our parents or grandparents are, we need to know what signs and signals to look for, and why, which is based on what endogamy looks like in people who know their heritage.

There’s no crystal ball – no definitive “one-way” arrow, but there are a series of indications that suggest endogamy.

Depending on the endogamous population you’re dealing with, those signs aren’t always the same.

If you’re sighing now, I understand – but that’s exactly WHY I wrote this article.

We’re covering a lot of ground, but these road markers are invaluable diagnostic tools.

I’ve previously written about endogamy in the articles:

Let’s start with definitions.

Pedigree Collapse and Endogamy

Pedigree collapse isn’t the same as endogamy. Pedigree collapse is when you have ancestors that repeat in your tree.

In this example, the parents of our DNA tester are first cousins, which means the tester shares great-grandparents on both sides and, of course, the same ancestors from there on back in their tree.

This also means they share more of those ancestors’ DNA than they would normally share.

John Smith and Mary Johnson are both in the tree twice, in the same position as great-grandparents. Normally, Tester Smith would carry approximately 12.5% of each of his great-grandparents’ DNA, assuming for illustration purposes that exactly 50% of each ancestor’s DNA is passed in each generation. In this case, due to pedigree collapse, 25% of Tester Smith’s DNA descends from John Smith, and another 25% descends from Mary Johnson, double what it would normally be. 25% is the amount of DNA contribution normally inherited from grandparents, not great-grandparents.

While we may find first cousin marriages a bit eyebrow-raising today, they were quite common in the past. Both laws and customs varied with the country, time, social norms, and religion.

Pedigree Collapse and Endogamy is NOT the Same

You might think that pedigree collapse and endogamy is one and the same, but there’s a difference. Pedigree collapse can lead to endogamy, but it takes more than one instance of pedigree collapse to morph into endogamy within a population. Population is the key word for endogamy.

The main difference is that pedigree collapse occurs with known ancestors in more recent generations for one person, while endogamy is longer-term and systemic in a group of people.

Picture a group of people, all descended from Tester Smith’s great-grandparents intermarrying. Now you have the beginnings of endogamy. A couple hundred or a few hundred years later, you have true endogamy.

In other words, endogamy is pedigree collapse on a larger scale – think of a village or a church.

My ancestors’ village of Schnait, in Germany, is shown above in 1685. One church and maybe 30 or 40 homes. According to church and other records, the same families had inhabited this village, and region, for generations. It’s a sure bet that both pedigree collapse and endogamy existed in this small community.

If pedigree collapse happens over and over again because there are no other people within the community to marry, then you have endogamy. In other words, with endogamy, you assuredly DO have historical pedigree collapse, generally back in time, often before you can identify those specific ancestors – because everyone descends from the same set of founders.

Endogamy Doesn’t Necessarily Indicate Recent Pedigree Collapse

With deep, historic endogamy, you don’t necessarily have recent pedigree collapse, and in fact, many people do not. Jewish people are a good example of this phenomenon. They shared ancestors for hundreds or thousands of years, depending on which group we are referring to, but in recent, known, generations, many Jewish people aren’t related. Still, their DNA often matches each other.

The good news is that there are telltale signs and signals of endogamy.

The bad news is that not all of these are obvious, meaning as an aid to people seeking clues about unknown close relatives, and other “signs” aren’t what they are believed to be.

Let’s step through each endogamy identifier, or “hint,” and then we will review how we can best utilize this information.

First, let’s take a look at groups that are considered to be endogamous.

Endogamous Groups

Jewish PeopleSpecifically groups that were isolated from other groups of Jewish (and other) people; Ashkenazi (Germany, Northern France, and diaspora), Sephardic (Spanish, Iberia, and diaspora), Mizrahi (Israel, Middle Eastern, and diaspora,) Ethiopian Jews, and possibly Jews from other locations such as Mountain Jews from Kazakhstan and the Caucasus.

AcadiansDescendants of about 60 French families who settled in “Acadia” beginning about 1604, primarily on the island of Nova Scotia, and intermarried among themselves and with the Mi’kmaq people. Expelled by the English in 1755, they were scattered in groups to various diasporic regions where they continued to intermarry and where their descendants are found today. Some Acadians became the Cajuns of Louisiana.

Anabaptist Protestant FaithsAmish, Mennonite, and Brethren (Dunkards) and their offshoots are Protestant religious sects founded in Europe in the 14th, 15th, and 16th centuries on the principle of baptizing only adults or people who are old enough to choose to follow the faith, or rebaptizing people who had been previously baptized as children. These Anabaptist faiths tend to marry within their own group or church and often expel those who marry outside of the faith. Many emigrated to the American colonies and elsewhere, seeking religious freedom. Occasionally those groups would locate in close proximity and intermarry, but not marry outside of other Anabaptist denominations.

Native American (Indigenous) People – all indigenous peoples found in North and South America before European colonization descended from a small number of original founders who probably arrived at multiple times.

Indigenous Pacific Islanders – Including indigenous peoples of Australia, New Zealand, and Hawaii prior to colonization. They are probably equally as endogamous as Native American people, but I don’t have specific examples to share.

Villages – European or other villages with little inflow or whose residents were restricted from leaving over hundreds of years.

Other groups may have significant multiple lines of pedigree collapse and therefore become endogamous over time. Some people from Newfoundland, French Canadians, and Mormons (Church of Jesus Christ of Latter-Day Saints) come to mind.

Endogamy is a process that occurs over time.

Endogamy and Unknown Relatives

If you know who your relatives are, you may already know you’re from an endogamous population, but if you’re searching for close relatives, it’s helpful to be able to determine if you have endogamous heritage, at least in recent generations.

If you know nothing about either parent, some of these tools won’t help you, at least not initially, but others will. However, as you add to your knowledge base, the other tools will become more useful.

If you know the identity of one parent, this process becomes at least somewhat easier.

In future articles, we will search specifically for parents and each of your four grandparents. In this article, I’ll review each of the diagnostic tools and techniques you can use to determine if you have endogamy, and perhaps pinpoint the source.

The Challenge

People with endogamous heritage are related in multiple, unknown ways, over many generations. They may also be related in known ways in recent generations.

If both of your parents share the SAME endogamous culture or group of relatives:

  • You may have significantly more autosomal DNA matches than people without endogamy, unless that group of people is under-sampled. Jewish people have significantly more matches, but Native people have fewer due to under-sampling.
  • You may experience a higher-than-normal cM (centiMorgan) total for estimated relationships, especially more distant relationships, 3C and beyond.
  • You will have many matches related to you on both your maternal and paternal sides.
  • Parts of your autosomal DNA will be the same on both your mother’s and father’s sides, meaning your DNA will be fully identical in some locations. (I’ll explain more in a minute.)

If either (or both) of your parents are from an endogamous population, you:

  • Will, in some cases, carry identifying Y and mitochondrial DNA that points to a specific endogamous group. This is true for Native people, can be true for Jewish people and Pacific Islanders, but is not true for Anabaptist people.

One Size Does NOT Fit All

Please note that there is no “one size fits all.”

Each or any of these tools may provide relevant hints, depending on:

  • Your heritage
  • How many other people have tested from the relevant population group
  • How many close or distant relatives have tested
  • If your parents share the same heritage
  • Your unique DNA inheritance pattern
  • If your parents, individually, were fully endogamous or only partly endogamous, and how far back generationally that endogamy occurred

For example, in my own genealogy, my maternal grandmother’s father was Acadian on his father’s side. While I’m not fully endogamous, I have significantly more matches through that line proportionally than on my other lines.

I have Brethren endogamy on my mother’s side via her paternal grandmother.

Endogamous ancestors are shown with red stars on my mother’s pedigree chart, above. However, please note that her maternal and paternal endogamous ancestors are not from the same endogamous population.

However, I STILL have fewer matches on my mother’s side in total than on my father’s side because my mother has recent Dutch and recent German immigrants which reduces her total number of matches. Neither of those lines have had as much time to produce descendants in the US, and Europe is under-sampled when compared with the US where more people tend to take DNA tests because they are searching for where they came from.

My father’s ancestors have been in the US since it was a British Colony, and I have many more cousins who have tested on his side than mother’s.

If you looked at my pedigree chart and thought to yourself, “that’s messy,” you’d be right.

The “endogamy means more matches” axiom does not hold true for me, comparatively, between my parents – in part because my mother’s German and Dutch lines are such recent immigrants.

The number of matches alone isn’t going to tell this story.

We are going to need to look at several pieces and parts for more information. Let’s start with ethnicity.

Ethnicity and Populations

Ethnicity can be a double-edged sword. It can tell you exactly nothing you couldn’t discern by looking in the mirror, or, conversely, it can be a wealth of information.

Ethnicity reveals the parts of the world where your ancestors originated. When searching for recent ancestors, you’re most interested in majority ethnicity, meaning the 50% of your DNA that you received from each of your parents.

Ethnicity results at each vendor are easy to find and relatively easy to understand.

This individual at FamilyTreeDNA is 100% Ashkenazi Jewish.

If they were 50% Jewish, we could then estimate, and that’s an important word, that either one of their parents was fully Jewish, and not the other, or that two of their grandparents were Jewish, although not necessarily on the same side.

On the other hand, my mother’s ethnicity, shown below, has nothing remarkable that would point to any majority endogamous population, yet she has two.

The only hint of endogamy from ethnicity would be her ~1% Americas, and that isn’t relevant for finding close relatives. However, minority ancestry is very relevant for identifying Native ancestors, which I wrote about, here.

You can correlate or track your ethnicity segments to specific ancestors, which I discussed in the article, Native American & Minority Ancestors Identified Using DNAPainter Plus Ethnicity Segments, here.

Since I wrote that article, FamilyTreeDNA has added the feature of ethnicity or population Chromosome Painting, based on where each of your populations fall on your chromosomes.

In this example on chromosome 1, I have European ancestry (blue,) except for the pink Native segment, which occurs on the following segment in the same location on my mother’s chromosome 1 as well.

Both 23andMe, and FamilyTreeDNA provide chromosome painting AND the associated segment information so you can identify the relevant ancestors.

Ancestry is in the process of rolling out an ethnicity painting feature, BUT, it has no segment or associated matching information. While it’s interesting eye candy, it’s not terribly useful beyond the ethnicity information that Ancestry already provides. However, Jonny Perl at DNAPainter has devised a way to estimate Ancestry’s start and stop locations, here. Way to go Jonny!

Now all you need to do is convince your Ancestry matches to upload their DNA file to one of the three databases, FamilyTreeDNA, MyHeritage, and GEDMatch, that accept transfers, aka uploads. This allows matching with segment data so that you can identify who matches you on that segment, track your ancestors, and paint your ancestral segments at DNAPainter.

I provided step-by-step instructions, here, for downloading your raw DNA file from each vendor in order to upload the file to another vendor.

Ethnicity Sides

Three of the four DNA testing vendors, 23andMe, FamilyTreeDNA, and recently, Ancestry, attempt to phase your ethnicity DNA, meaning to assign it to one parental “side” or the other – both in total and on each chromosome.

Here’s Ancestry’s SideView, where your DNA is estimated to belong to parent 1 and parent 2. I detailed how to determine which side is which, here, and while that article was written specifically pertaining to Ancestry’s SideView, the technique is relevant for all the vendors who attempt to divide your DNA into parents, a technique known as phasing.

I say “attempt” because phasing may or may not be accurate, meaning the top chromosome may not always be parent 1, and the bottom chromosome may not always be chromosome 2.

Here’s an example at 23andMe.

See the two yellow segments. They are both assigned as Native. I happen to know one is from the mother and one is from the father, yet they are both displayed on the “top” chromosome, which one would interpret to be the same parent.

I am absolutely positive this is not the case because this is a close family member, and I have the DNA of the parent who contributed the Native segment on chromosome 1, on the top chromosome. That parent does not have a Native segment on chromosome 2 to contribute. So that Native segment had to be contributed by the other parent, but it’s also shown on the top chromosome.

The DNA segments circled in purple belong together on the same “side” and were contributed to the tester by the same parent. The Native segment on chromosome 2 abuts a purple African segment, suggesting perhaps that the ancestor who contributed that segment was mixed between those ethnicities. In the US, that suggests enslavement.

The other African segments, circled, are shown on the second chromosome in each pair.

To be clear, parent 1 is not assigned by the vendors to either mother or father and will differ by person. Your parent 1, or the parent on the top chromosome may be your mother and another person’s parent 1 may be their father.

As shown in this example, parents can vary by chromosome, a phenomenon known as “strand swap.” Occasionally, the DNA can even be swapped within a chromosome assignment.

You can, however, get an idea of the division of your DNA at any specific location. As shown above, you can only have a maximum of two populations of DNA on any one chromosome location.

In our example above, this person’s majority ancestry is European (blue.) On each chromosome where we find a minority segment, the opposite chromosome in the same location is European, meaning blue.

Let’s look at another example.

At FamilyTreeDNA, the person whose ethnicity painting is shown below has a Native American (pink) ancestor on their father’s side. FamilyTreeDNA has correctly phased or identified their Native segments as all belonging to the second chromosome in each pair.

Looking at chromosome 18, for example, most of their father’s chromosome is Native American (pink). The other parent’s chromosome is European (dark blue) at those same locations.

If one of the parents was of one ethnicity, and the other parent is a completely different ethnicity, then one bar of each chromosome would be all pink, for example, and one would be entirely blue, representing the other ethnicity.

Phasing ethnicity or populations to maternal and paternal sides is not foolproof, and each chromosome is phased individually.

Ethnicity can, in some cases, give you a really good idea of what you’re dealing with in terms of heritage and endogamy.

If someone had an Ashkenazi Jewish father and European mother, for example, one copy of each chromosome would be yellow (Ashkenazi Jewish), and one would be blue (European.)

However, if each of their parents were half European Jewish and half European (not Jewish), then their different colored segments would be scattered across their entire set of chromosomes.

In this case, both of the tester’s parents are mixed – European Jewish (green) and Western Europe (blue.) We know both parents are admixed from the same two populations because in some locations, both parents contributed blue (Western Europe), and in other locations, both contributed Jewish (green) segments.

Both MyHeritage and Ancestry provide a secondary tool that’s connected to ethnicity, but different and generally in more recent times.

Ancestry’s DNA Communities

While your ethnicity may not point to anything terribly exciting in terms of endogamy, Genetic Communities might. Ancestry says that a DNA Community is a group of people who share DNA because their relatives recently lived in the same place at the same time, and that communities are much smaller than ethnicity regions and reach back only about 50-300 years.

Based on the ancestors’ locations in the trees of me and my matches, Ancestry has determined that I’m connected to two communities. In my case, the blue group is clearly my father’s line. The orange group could be either parent, or even a combination of both.

My endogamous Brethren could be showing up in Maryland, Pennsylvania, and Ohio, but it’s uncertain, in part, because my father’s ancestral lines are found in Virginia, West Virginia, and Maryland too.

These aren’t useful for me, but they may be more useful for fully endogamous people, especially in conjunction with ethnicity.

My Acadian cousin’s European ethnicity isn’t informative.

However, viewing his DNA Communities puts his French heritage into perspective, especially combined with his match surnames.

I wrote about DNA Communities when it was introduced with the name Genetic Communities, here.

MyHeritage’s Genetic Groups

MyHeritage also provides a similar feature that shows where my matches’ ancestors lived in the same locations as mine.

One difference, though, is that testers can adjust their ethnicity results confidence level from high, above, to low, below where one of my Genetic Groups overlaps my ethnicity in the Netherlands.

You can also sort your matches by Genetic Groups.

The results show you not only who is in the group, but how many of your matches are in that group too, which provides perspective.

I wrote about Genetic Groups, here.

Next, let’s look at how endogamy affects your matches.

Matches

The number of matches that a person has who is from an entirely endogamous community and a person with no endogamy may be quite different.

FamilyTreeDNA provides a Family Matching feature that triangulates your matches and assigns them to your paternal or maternal side by using known matches that you have linked to their profile cards in your tree. You must link people for the Family Matching feature known as “bucketing” to be enabled.

The people you link are then processed for shared matches on the same chromosome segment(s). Triangulated individuals are then deposited in your maternal, paternal, and both buckets.

Obviously, your two parents are the best people to link, but if they haven’t tested (or uploaded their DNA file from another vendor) and you have other known relatives, link them using the Family Tree tab at the top of your personal page.

I uploaded my Ancestry V4 kit to use as an example for linking. Let’s pretend that’s my sister. If I had not already linked my Ancestry V4 kit to “my sister’s” profile card, I’d want to do that and link other known individuals the same way. Just drag and drop the match to the correct profile card.

Note that a full or half sibling will be listed as such at FamilyTreeDNA, but an identical twin will show as a potential parent/child match to you. You’re much more likely to find a parent than an identical twin, but just be aware.

I’ve created a table of FamilyTreeDNA bucketed match results, by category, comparing the number of matches in endogamous categories with non-endogamous.

Total Matches Maternal Matches Paternal Matches Both % Both % DNA Unassigned
100% Jewish 34,637 11,329 10,416 4,806 13.9 23.3
100% Jewish 32,973 10,700 9,858 4,606 14 23.7
100% Jewish 32,255 9,060 10,970 3,892 12 25.8
75% Jewish 24,232 11,846 Only mother linked Only mother linked Only mother linked
100% Acadian 8093 3826 2299 1062 13 11
100% Acadian 7828 3763 1825 923 11.8 17
Not Endogamous 6760 3845 1909 13 0.19 14.5
Not Endogamous 7723 1470 3317 6 0.08 38
100% Native American 1,115 Unlinked Unlinked Unlinked
100% Native American 885 290 Unknown Can’t calculate without at least one link on both sides

The 100% Jewish, Acadian, and Not Endogamous testers both have linked their parents, so their matches, if valid (meaning not identical by chance, which I discussed here,) will match them plus one or the other parent.

One person is 75% Jewish and has only linked their Jewish mother.

The Native people have not tested their parents, and the first Native person has not linked anyone in their tree. The second Native person has only linked a few maternal matches, but their mother has not tested. They are seeking their father.

It’s very difficult to find people who are fully Native as testers. Furthermore, Native people are under-sampled. If anyone knows of fully Native (or other endogamous) people who have tested and linked their parents or known relatives in their trees, and will allow me to use their total match numbers anonymously, please let me know.

As you can see, Jewish, Acadian, and Native people are 100% endogamous, but many more Jewish people than Native people have tested, so you CAN’T judge endogamy by the total number of matches alone.

In fact, in order:

  • Fully Jewish testers have about 4-5 times as many matches as the Acadian and Non-endogamous testers
  • Acadian and Non-endogamous testers have about 5-6 times as many matches as the Native American testers
  • Fully Jewish people have about 30 times more matches than the Native American testers

If a person’s endogamy with a particular population is only on their maternal or paternal side, they won’t have a significant number of people related to both sides, meaning few people will fall into the “Both” bucket. People that will always be found in the ”Both” bucket are full siblings and their descendants, along with descendants of the tester, assuming their match is linked to their profiles in the tester’s tree.

In the case of our Jewish testers, you can easily see that the “Both” bucket is very high. The Acadians are also higher than one would reasonably expect without endogamy. A non-endogamous person might have a few matches on both sides, assuming the parents are not related to each other.

A high number of “Both” matches is a very good indicator of endogamy within the same population on both parents’ sides.

The percentage of people who are assigned to the “Both” bucket is between 11% and 14% in the endogamous groups, and less than 1% in the non-endogamous group, so statistically not relevant.

As demonstrated by the Native people compared to the Jewish testers, the total number of matches can be deceiving.

However, being related to both parents, as indicated by the “Both” bucket, unless you have pedigree collapse, is a good indicator of endogamy.

Of course, if you don’t know who your relatives are, you can’t link them in your tree, so this type of “hunt” won’t generally help people seeking their close family members.

However, you may notice that you’re matching people PLUS both of their parents. If that’s the case, start asking questions of those matches about their heritage.

A very high number of total matches, as compared to non-endogamous people, combined with some other hints might well point to Jewish heritage.

I included the % DNA Unassigned category because this category, when both parents are linked, is the percentage of matches by chance, meaning the match doesn’t match either of the tester’s parents. All of the people with people listed in “Both” categories have linked both of their parents, not just maternal and paternal relatives.

Matching Location at MyHeritage

MyHeritage provides a matching function by location. Please note that it’s the location of the tester, but that may still be quite useful.

The locations are shown in the most-matches to least-matches order. Clicking on the location shows the people who match you who are from that location. This would be the most useful in situations where recent immigration has occurred. In my case, my great-grandfather from the Netherlands arrived in the 1860s, and my German ancestors arrived in the 1850s. Neither of those groups are endogamous, though, unless it would be on a village level.

AutoClusters

Let’s shift to Genetic Affairs, a third-party tool available to everyone.

Using their AutoCluster function, Genetic Affairs clusters your matches together who match both each other and you.

This is an example of the first few clusters in my AutoCluster. You can see that I have several colored clusters of various sizes, but none are huge.

Compare that to the following endogamous cluster, sample courtesy of EJ Blom at Genetic Affairs.

If your AutoCluster at Genetic Affairs looks something like this, a huge orange blob in the upper left hand corner, you’re dealing with endogamy.

Please also note that the size of your cluster is also a function of both the number of testers and the match threshold you select. I always begin by using the defaults. I wrote about using Genetic Affairs, here.

If you tested at or transferred to MyHeritage, they too license AutoClusters, but have optimized the algorithm to tease out endogamous matches so that their Jewish customers, in particular, don’t wind up with a huge orange block of interrelated people.

You won’t see the “endogamy signature” huge cluster in the corner, so you’re less likely to be able to discern endogamy from a MyHeritage cluster alone.

The commonality between these Jewish clusters at MyHeritage is that they all tend to be rather uniform in size and small, with lots of grey connecting almost all the blocks.

Grey cells indicate people who match people in two colored groups. In other words, there is often no clear division in clusters between the mother’s side and the father’s side in Jewish clusters.

In non-endogamous situations, even if you can’t identify the parents, the clusters should still fall into two sides, meaning a group of clusters for each parent’s side that are not related to each other.

You can read more about Genetic Affairs clusters and their tools, here. DNAGedcom.com also provides a clustering tool.

Endogamous Relationships

Endogamous estimated relationships are sometimes high. Please note the word, “sometimes.”

Using the Shared cM Project tool relationship chart, here, at DNAPainter, people with heavy endogamy will discover that estimated relationships MAY be on the high side, or the relationships may, perhaps, be estimated too “close” in time. That’s especially true for more distant relationships, but surprisingly, it’s not always true. The randomness of inheritance still comes into play, and so do potential unknown relatives. Hence, the words “may” are bolded and underscored.

Unfortunately, it’s often stated as “conventional wisdom” that Jewish matches are “always” high, and first cousins appear as siblings. Let’s see what the actual data says.

At DNAPainter, you can either enter the amount of shared DNA (cM), or the percent of shared DNA, or just use the chart provided.

I’ve assembled a compilation of close relationships in kits that I have access to or from people who were generous enough to share their results for this article.

I’ve used Jewish results, which is a highly endogamous population, compared with non-endogamous testers.

The “Jewish Actual” column reports the total amount of shared DNA with that person. In other words, someone to their grandparent. The Average Range is the average plus the range from DNAPainter. The Percent Difference is the % difference between the actual number and the DNAPainter average.

You’ll see fully Jewish testers, at left, matching with their family members, and a Non-endogamous person, at right, matching with their same relative.

Relationship Jewish Actual Percent Difference than Average Average -Range Non-endogamous Actual Percent Difference than Average
Grandparent 2141 22 1754 (984-2482) 1742 <1 lower
Grandparent 1902 8.5 1754 (984-2482) 1973 12
Sibling 3039 16 2613 (1613-3488) 2515 3.5 lower
Sibling 2724 4 2613 (1613-3488) 2761 5.5
Half-Sibling 2184 24 1759 (1160-2436) 2127 21
Half-Sibling 2128 21 1759 (1160-2436) 2352 34
Aunt/Uncle 2066 18.5 1741 (1201-2282) 1849 6
Aunt/Uncle 2031 16.5 1741 (1201-2282) 2097 20
1C 1119 29 866 (396-1397) 959 11
1C 909 5 866 (396-1397) 789 9 lower
1C1R 514 19 433 (102-980) 467 8
1C1R 459 6 433 (102-980) 395 9 lower

These totals are from FamilyTreeDNA except one from GEDMatch (one Jewish Half-sibling).

Totals may vary by vendor, even when matching with the same person. 23andMe includes the X segments in the total cMs and also counts fully identical segments twice. MyHeritage imputation seems to err on the generous side.

However, in these dozen examples:

  • You can see that the Jewish actual amount of DNA shared is always more than the average in the estimate.
  • The red means the overage is more than 100 cM larger.
  • The percentage difference is probably more meaningful because 100 cM is a smaller percentage of a 1754 grandparent connection than compared to a 433 cM 1C1R.

However, you can’t tell anything about endogamy by just looking at any one sample, because:

  • Some of the Non-Endogamous matches are high too. That’s just the way of random inheritance.
  • All of the actual Jewish match numbers are within the published ranges, but on the high side.

Furthermore, it can get more complex.

Half Endogamous

I requested assistance from Jewish genealogy researchers, and a lovely lady, Sharon, reached out, compiled her segment information, and shared it with me, granting permission to share with you. A HUGE thank you to Sharon!

Sharon is half-Jewish via one parent, and her half-sibling is fully Jewish. Their half-sibling match to each other at Ancestry is 1756 cM with a longest segment of 164 cM.

How does Jewish matching vary if you’re half-Jewish versus fully Jewish? Let’s look at 21 people who match both Sharon and her fully Jewish half-sibling.

Sharon shared the differences in 21 known Jewish matches with her and her half-sibling. I’ve added the Relationship Estimate Range from DNAPainter and colorized the highest of the two matches in yellow. Bolding in the total cM column shows a value above the average range for that relationship.

Total Matching cMs is on the left, with Longest Segment on the right.

While this is clearly not a scientific study, it is a representative sample.

The fully Jewish sibling carries more Jewish DNA, which is available for other Jewish matches to match as a function of endogamy (identical by chance/population), so I would have expected the fully Jewish sibling to match most if not all Jewish testers at a higher level than the half-Jewish sibling.

However, that’s not universally what we see.

The fully Jewish sibling is not always the sibling with the highest number of matches to the other Jewish testers, although the half-Jewish tester has the larger “Longest Segment” more often than not.

Approximately two-thirds of the time (13/21), the fully Jewish person does have a higher total matching cM, but about one-third of the time (8/21), the half-Jewish sibling has a higher matching cM.

About one-fourth of the time (5/21), the fully Jewish sibling has the longest matching segment, and about two-thirds of the time (13/21), the half-Jewish sibling does. In three cases, or about 14% of the time, the longest segment is equal which may indicate that it’s the same segment.

Because of endogamy, Jewish matches are more likely to have:

  • Larger than average total cM for the specific relationship
  • More and smaller matching segments

However, as we have seen, neither of those are definitive, nor always true. Jewish matches and relationships are not always overestimated.

Ancestry and Timber

Please note that Ancestry downweights some matches by removing some segments using their Timber algorithm. Based on my matches and other accounts that I manage, Ancestry does not downweight in the 2-3rd cousin category, which is 90 cM and above, but they do begin downweighting in the 3-4th cousin category, below 90 cM, where my “Extended Family” category begins.

If you’ve tested at Ancestry, you can check for yourself.

By clicking on the amount of DNA you share with your match on your match list at Ancestry, shown above, you will be taken to another page where you will be able to view the unweighted shared DNA with that match, meaning the amount of DNA shared before the downweighting and removal of some segments, shown below.

Given the downweighting, and the information in the spreadsheet provided by Sharon, it doesn’t appear that any of those matches would have been in a category to be downweighted.

Therefore, for these and other close matches, Timber wouldn’t be a factor, but would potentially be in more distant matches.

Endogamous Segments

Endogamous matches tend to have smaller and more segments. Small amounts of matching DNA tend to skew the total DNA cM upwards.

How and why does this happen?

Ancestral DNA from further back in time tends to be broken into smaller segments.

Sometimes, especially in endogamous situations, two smaller segments, at one time separated from each other, manage to join back together again and form a match, but the match is only due to ancestral segments – not because of a recent ancestor.

Please note that different vendors have different minimum matching cM thresholds, so smaller matches may not be available at all vendors. Remember that factors like Timber and imputation can affect matching as well.

Let’s take a look at an example. I’ve created a chart where two ancestors have their blue and pink DNA broken into 4 cM segments.

They have children, a blue child and a pink child, and the two children, shown above, each inherited the same blue 4 cM segment and the same pink 4 cM segment from their respective parents. The other unlabeled pink and blue segments are not inherited by these two children, so those unlabeled segments are irrelevant in this example.

The parents may have had other children who inherited those same 4 cM labeled pink and blue segments as well, and if not, the parents’ siblings were probably passing at least some of the same DNA down to their descendants too.

The blue and pink children had children, and their children had children – for several generations.

Time passed, and their descendants became an endogamous community. Those pink and blue 4 cM segments may at some time be lost during recombination in the descendants of each of their children, shown by “Lost pink” and “Lost blue.”

However, because there is only a very limited amount of DNA within the endogamous community, their descendants may regain those same segments again from their “other parent” during recombination, downstream.

In each generation, the DNA of the descendant carrying the original blue or pink DNA segment is recombined with their partner. Given that the partners are both members of the same endogamous community, the two people may have the same pink and/or blue DNA segments. If one parent doesn’t carry the pink 4 cM segment, for example, their offspring may receive that ancestral pink segment from the other parent.

They could potentially, and sometimes do, receive that ancestral segment from both parents.

In our example, the descendants of the blue child, at left, lost the pink 4 cM segment in generation 3, but a few generations later, in generation 11, that descendant child inherited that same pink 4 cM segment from their other parent. Therefore, both the 4 cM blue and 4 cM pink segments are now available to be inherited by the descendants in that line. I’ve shown the opposite scenario in the generational inheritance at right where the blue segment is lost and regained.

Once rejoined, that pink and blue segment can be passed along together for generations.

The important part, though, is that once those two segments butt up against each other again during recombination, they aren’t just two separate 4 cM segments, but one segment that is 8 cM long – that is now equal to or above the vendors’ matching threshold.

This is why people descended from endogamous populations often have the following matching characteristics:

  • More matches
  • Many smaller segment matches
  • Their total cM is often broken into more, smaller segments

What does more, smaller segments, look like, exactly?

More, Smaller Segments

All of our vendors except Ancestry have a chromosome browser for their customers to compare their DNA to that of their matches visually.

Let’s take a look at some examples of what endogamous and non-endogamous matches look like.

For example, here’s a screen shot of a random Jewish second cousin match – 298 cM total, divided into 12 segments, with a longest segment of 58 cM,

A second Jewish 2C with 323 cM total, across 19 segments, with a 69 cM longest block.

A fully Acadian 2C match with 600 cM total, across 27 segments, with a longest segment of 69 cM.

A second Acadian 2C with 332 cM total, across 20 segments, with a longest segment of 42 cM.

Next, a non-endogamous 2C match with 217 cM, across 7 segments, with a longest segment of 72 cM.

Here’s another non-endogamous 2C example, with 169 shared cM, across 6 segments, with a longest segment of 70 cM.

Here’s the second cousin data in a summary table. The take-away from this is the proportion of total segments

Tester Population Total cM Longest Block Total Segments
Jewish 2C 298 58 12
Jewish 2C 323 69 19
Acadian 2C 600 69 27
Acadian 2C 332 42 20
Non-endogamous 2C 217 72 7
Non-endogamous 2C 169 70 6

You can see more examples and comparisons between Native American, Jewish and non-endogamous DNA individuals in the article, Concepts – Endogamy and DNA Segments.

I suspect that a savvy mathematician could predict endogamy based on longest block and total segment information.

Lara Diamond, a mathematician, who writes at Lara’s Jewnealogy might be up for this challenge. She just published compiled matching and segment information in her Ashkenazic Shared DNA Survey Results for those who are interested. You can also contribute to Laura’s data, here.

Endogamy, Segments, and Distant Relationships

While not relevant to searching for close relatives, heavily endogamous matches 3C and more distant, to quote one of my Jewish friends, “dissolve into a quagmire of endogamy and are exceedingly difficult to unravel.”

In my own Acadian endogamous line, I often simply have to label them “Acadian” because the DNA tracks back to so many ancestors in different lines. In other words, I can’t tell which ancestor the match is actually pointing to because the same DNA segments or segments is/are carried by several ancestors and their descendants due to founder effect.

The difference with the Acadians is that we can actually identify many or most of them, at least at some point in time. As my cousin, Paul LeBlanc, once said, if you’re related to one Acadian, you’re related to all Acadians. Then he proceeded to tell me that he and I are related 137 different ways. My head hurts!

It’s no wonder that endogamy is incredibly difficult beyond the first few generations when it turns into something like multi-colored jello soup.

“Are Your Parents Related?” Tool

There’s another tool that you can utilize to determine if your parents are related to each other.

To determine if your parents are related to each other, you need to know about ROH, or Runs of Homozygosity (ROH).

ROH means that the DNA on both strands or copies of the same chromosome is identical.

For a few locations in a row, ROH can easily happen just by chance, but the longer the segment, the less likely that commonality occurs simply by chance.

The good news is that you don’t need to know the identity of either of your parents. You don’t need either of your parent’s DNA tests – just your own. You’ll need to upload your DNA file to GEDmatch, which is free.

Click on “Are your parents related?”

GEDMatch analyzes your DNA to see if any of your DNA, above a reasonable matching threshold, is identical on both strands, indicating that you inherited the exact same DNA from both of your parents.

A legitimate match, meaning one that’s not by chance, will include many contiguous matching locations, generally a minimum of 500 SNPs or locations in a row. GEDmatch’s minimum threshold for identifying identical ancestral DNA (ROH) is 200 cM.

Here’s my result, including the graphic for the first two chromosomes. Notice the tiny green bars that show identical by chance tiny sliver segments.

I have no significant identical DNA, meaning my parents are not related to each other.

Next, let’s look at an endogamous example where there are small, completely identical segments across a person’s chromosome

This person’s Acadian parents are related to each other, but distantly.

Next, let’s look at a Jewish person’s results.

You’ll notice larger green matching ROH, but not over 200 contiguous SNPs and 7 cM.

GEDMatch reports that this Jewish person’s parents are probably not related within recent generations, but it’s clear that they do share DNA in common.

People whose parents are distantly related have relatively small, scattered matching segments. However, if you’re seeing larger ROH segments that would be large enough to match in a genealogical setting, meaning multiple greater than 7 cM and 500 SNPs,, you may be dealing with a different type of situation where cousins have married in recent generations. The larger the matching segments, generally, the closer in time.

Blogger Kitty Cooper wrote an article, here, about discovering that your parents are related at the first cousin level, and what their GEDMatch “Are Your Parents Related” results look like.

Let’s look for more clues.

Surnames

There MAY be an endogamy clue in the surnames of the people you match.

Viewing surnames is easier if you download your match list, which you can do at every vendor except Ancestry. I’m not referring to the segment data, but the information about your matches themselves.

I provided instructions in the recent article, How to Download Your DNA Match Lists and Segment Files, here.

If you suspect endogamy for any reason, look at your closest matches and see if there is a discernable trend in the surnames, or locations, or any commonality between your matches to each other.

For example, Jewish, Acadian, and Native surnames may be recognizable, as may locations.

You can evaluate in either or both of two ways:

  • The surnames of your closest matches. Closest matches listed first will be your default match order.
  • Your most frequently occurring surnames, minus extremely common names like Smith, Jones, etc., unless they are also in your closest matches. To utilize this type of matching, sort the spreadsheet in surname order and then scan or count the number of people with each surname.

Here are some examples from our testers.

Jewish – Closest surname matches.

  • Roth
  • Weiss
  • Goldman
  • Schonwald
  • Levi
  • Cohen
  • Slavin
  • Goodman
  • Sender
  • Trebatch

Acadian – Closest surname matches.

  • Bergeron
  • Hebert
  • Bergeron
  • Marcum
  • Muise
  • Legere
  • Gaudet
  • Perry
  • Verlander
  • Trombley

Native American – Closest surname matches.

  • Ortega
  • Begay
  • Valentine
  • Hayes
  • Montoya
  • Sun Bear
  • Martin
  • Tsosie
  • Chiquito
  • Yazzie

You may recognize these categories of surnames immediately.

If not, Google is your friend. Eliminate common surnames, then Google for a few together at a time and see what emerges.

The most unusual surnames are likely your best bets.

Projects

Another way to get some idea of what groups people with these surnames might belong to is to enter the surname in the FamilyTreeDNA surname search.

Go to the main FamilyTreeDNA page, but DO NOT sign on.

Scroll down until you see this image.

Type the surname into the search box. You’ll see how many people have tested with that surname, along with projects where project administrators have included that surname indicating that the project may be of interest to at least some people with that surname.

Here’s a portion of the project list for Cohen, a traditional Jewish surname.

These results are for Muise, an Acadian surname.

Clicking through to relevant surname projects, and potentially contacting the volunteer project administrator can go a very long way in helping you gather and sift information. Clearly, they have an interest in this topic.

For example, here’s the Muise surname in the Acadian AmerIndian project. Two great hints here – Acadian heritage and Halifax, Nova Scotia.

Repeat for the balance of surnames on your list to look for commonalities, including locations on the public project pages.

Locations

Some of the vendor match files include location information. Each person on your match list will have the opportunity at the vendor where they tested to include location information in a variety of ways, either for their ancestors or themselves.

Where possible, it’s easiest to sort or scan the download file for this type of information.

Ancestry does not provide or facilitate a match list, but you can still create your own for your closest 20 or 30 matches in a spreadsheet.

MyHeritage provides common surname and ancestral location information for every match. How cool is that!

Y DNA, Mitochondrial DNA, and Endogamy

Haplogroups for both Y and mitochondrial DNA can indicate and sometimes confirm endogamy. In other cases, the haplogroup won’t help, but the matches and their location information just might.

FamilyTreeDNA is the only vendor that provides Y DNA and mitochondrial DNA tests that include highly granular haplogroups along with matches and additional tools.

23andMe provides high-level haplogroups which may or may not be adequate to pinpoint a haplogroup that indicates endogamy.

Of course, only males carry Y DNA that tracks to the direct paternal (surname) line, but everyone carries their mother’s mitochondrial DNA that represents their mother’s mother’s mother’s, or direct matrilineal line.

Some haplogroups are known to be closely associated with particular ethnicities or populations, like Native Americans, Pacific Islanders, and some Jewish people.

Haplogroups reach back in time before genealogy and can give us a sense of community that’s not available by either looking in the mirror or through traditional records.

This Native American man is a member of high-level haplogroup Q-M242. However, some men who carry this haplogroup are not Native, but are of European or Middle Eastern origin.

I entered the haplogroup in the FamilyTreeDNA Discover tool, which I wrote about, here.

Checking the information about this haplogroup reveals that their common ancestor descended from an Asian man about 30,000 years ago.

The migration path in the Americans explains why this person would have an endogamous heritage.

Our tester would receive a much more refined haplogroup if he upgraded to the Big Y test at FamilyTreeDNA, which would remove all doubt.

However, even without additional testing, information about his matches at FamilyTreeDNA may be very illuminating.

The Q-M242 Native man’s Y DNA matches men with more granular haplogroups, shown above, at left. On the Haplogroup Origins report, you can see that these people have all selected the “US (Native American)” country option.

Another useful tool would be to check the public Y haplotree, here, and the public mitochondrial tree here, for self-reported ancestor location information for a specific haplogroup.

Here’s an example of mitochondrial haplogroup A2 and a few subclades on the public mitochondrial tree. You can see that the haplogroup is found in Mexico, the US (Native,) Canada, and many additional Caribbean, South, and Central American countries.

Of course, Y DNA and mitochondrial DNA (mtDNA) tell a laser-focused story of one specific line, each. The great news, if you’re seeking information about your mother or father, the Y is your father’s direct paternal (surname) line, and mitochondrial is your mother’s direct matrilineal line.

Y and mitochondrial DNA results combined with ethnicity, autosomal matching, and the wide range of other tools that open doors, you will be able to reveal a great deal of information about whether you have endogamous heritage or not – and if so, from where.

I’ve provided a resource for stepping through and interpreting your Y DNA results, here, and mitochondrial DNA, here.

Discover for Y DNA Only

If you’re a female, you may feel left out of Y DNA testing and what it can tell you about your heritage. However, there’s a back door.

You can utilize the Y DNA haplogroups of your closest autosomal matches at both FamilyTreeDNA and 23andMe to reveal information

Haplogroup information is available in the download files for both vendors, in addition to the Family Finder table view, below, at FamilyTreeDNA, or on your individual matches profile cards at both 23andMe and FamilyTreeDNA.

You can enter any Y DNA haplogroup in the FamilyTreeDNA Discover tool, here.

You’ll be treated to:

  • Your Haplogroup Story – how many testers have this haplogroup (so far), where the haplogroup is from, and the haplogroup’s age. In this case, the haplogroup was born in the Netherlands about 250 years ago, give or take 200 years. I know that it was 1806 or earlier based on the common ancestor of the men who tested.
  • Country Frequency – heat map of where the haplogroup is found in the world.
  • Notable Connections – famous and infamous (this haplogroup’s closest notable person is Leo Tolstoy).
  • Migration Map – migration path out of Africa and through the rest of the world.
  • Ancient Connections – ancient burials. His closest ancient match is from about 1000 years ago in Ukraine. Their shared ancestor lived about 2000 years ago.
  • Suggested Projects – based on the surname, projects that other matches have joined, and haplogroups.
  • Scientific Details – age estimates, confidence intervals, graphs, and the mutations that define this haplogroup.

I wrote about the Discover tool in the article, FamilyTreeDNA DISCOVER Launches – Including Y DNA Haplogroup Ages.

Endogamy Tools Summary Tables

Endogamy is a tough nut sometimes, especially if you’re starting from scratch. In order to make this topic a bit easier and to create a reference tool for you, I’ve created three summary tables.

  • Various endogamy-related tools available at each vendor which will or may assist with evaluating endogamy
  • Tools and their ability to detect endogamy in different groups
  • Tools best suited to assist people seeking information about unknown parents or grandparents

Summary of Endogamy Tools by Vendor

Please note that GEDMatch is not a DNA testing vendor, but they accept uploads and do have some tools that the testing vendors do not.

 Tool 23andMe Ancestry FamilyTreeDNA MyHeritage GEDMatch
Ethnicity Yes Yes Yes Yes Use the vendors
Ethnicity Painting Yes + segments Yes, limited Yes + segments Yes
Ethnicity Phasing Yes Partial Yes No
DNA Communities No Yes No No
Genetic Groups No No No Yes
Family Matching aka Bucketing No No Yes No
Chromosome Browser Yes No Yes Yes Yes
AutoClusters Through Genetic Affairs No Through Genetic Affairs Yes, included Yes, with subscription
Match List Download Yes, restricted # of matches No Yes Yes Yes
Projects No No Yes No
Y DNA High-level haplogroup only No Yes, full haplogroup with Big Y, matching, tools, Discover No
Mitochondrial DNA High-level haplogroup only No Yes, full haplogroup with mtFull, matching, tools No
Public Y Tree No No Yes No
Public Mito Tree No No Yes No
Discover Y DNA – public No No Yes No
ROH No No No No Yes

Summary of Endogamous Populations Identified by Each Tool

The following chart provides a guideline for which tools are useful for the following types of endogamous groups. Bolded tools require that both parents be descended from the same endogamous group, but several other tools give more definitive results with higher amounts of endogamy.

Y and mitochondrial DNA testing are not affected by admixture, autosomal DNA or anything from the “other” parent.

Tool Jewish Acadian Anabaptist Native Other/General
Ethnicity Yes No No Yes Pacific Islander
Ethnicity Painting Yes No No Yes Pacific Islander
Ethnicity Phasing Yes, if different No No Yes, if different Pacific Islander, if different
DNA Communities Yes Possibly Possibly Yes Pacific Islander
Genetic Groups Yes Possibly Possibly Yes Pacific Islander
Family Matching aka Bucketing Yes Yes Possibly Yes Pacific Islander
Chromosome Browser Possibly Possibly Yes, once segments or ancestors identified Possibly Pacific Islander, possibly
Total Matches Yes, compared to non-endogamous No No No No, unknown
AutoClusters Yes Yes Uncertain, probably Yes Pacific Islander
Estimated Relationships High Not always Sometimes No Sometimes Uncertain, probably
Relationship Range High Possibly, sometimes Possibly Possibly Possibly Pacific Islander, possibly
More, Smaller Segments Yes Yes Probably Yes Pacific Islander, probably
Parents Related Some but minimal Possibly Uncertain Probably similar to Jewish Uncertain, Possibly
Surnames Probably Probably Probably Not Possibly Possibly
Locations Possibly Probably Probably Not Probably Probably Pacific Islander
Projects Probably Probably Possibly Possibly Probably Pacific Islander
Y DNA Yes, often Yes, often No Yes Pacific Islander
Mitochondrial DNA Yes, often Sometimes No Yes Pacific Islander
Y public tree Probably not alone No No Yes Pacific Islander
MtDNA public tree Probably not No No Yes Pacific Islander
Y DNA Discover Yes Possibly Probably not, maybe projects Yes Pacific Islander

Summary of Endogamy Tools to Assist People Seeking Unknown Parents and Grandparents

This table provides a summary of when each of the various tools can be useful to:

  • People seeking unknown close relatives
  • People who already know who their close relatives are, but are seeking additional information or clues about their genealogy

I considered rating these on a 1 to 10 scale, but the relative usefulness of these tools is dependent on many factors, so different tools will be more or less useful to different people.

For example, ethnicity is very useful if someone is admixed from different populations, or even 100% of a specific endogamous population. It’s less useful if the tester is 100% European, regardless of whether they are seeking close relatives or not. Conversely, even “vanilla” ethnicity can be used to rule out majority or recent admixture with many populations.

Tools Unknown Close Relative Seekers Known Close Relatives – Enhance Genealogy
Ethnicity Yes, to identify or rule out populations Yes
Ethnicity Painting Yes, possibly, depending on population Yes, possibly, depending on population
Ethnicity Phasing Yes, possibly, depending on population Yes, possibly, depending on population
DNA Communities Yes, possibly, depending on population Yes, possibly, depending on population
Genetic Groups Possibly, depending on population Possibly, depending on population
Family Matching aka Bucketing Not if parents are entirely unknown, but yes if one parent is known Yes
Chromosome Browser Unlikely Yes
AutoClusters Yes Yes, especially at MyHeritage if Jewish
Estimated Relationships High Not No
Relationship Range High Not reliably No
More, Smaller Segments Unlikely Unlikely other than confirmation
Match List Download Yes Yes
Surnames Yes Yes
Locations Yes Yes
Projects Yes Yes
Y DNA Yes, males only, direct paternal line, identifies surname lineage Yes, males only, direct paternal line, identifies and correctly places surname lineage
Mitochondrial DNA Yes, both sexes, direct matrilineal line only Yes, both sexes, direct matrilineal line only
Public Y Tree Yes for locations Yes for locations
Public Mito Tree Yes for locations Yes for locations
Discover Y DNA Yes, for heritage information Yes, for heritage information
Parents Related – ROH Possibly Less useful

Acknowledgments

A HUGE thank you to several people who contributed images and information in order to provide accurate and expanded information on the topic of endogamy. Many did not want to be mentioned by name, but you know who you are!!!

If you have information to add, please post in the comments.

_____________________________________________________________

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How to Download Your DNA Match Lists & Segment Files

If you’ve taken an autosomal DNA test and you’re working to determine how your matches are related to you, meaning which ancestors you share, you’ll want to download your DNA match list.

There are three types of files that you can potentially download from each of the major autosomal DNA testing vendors.

Raw DNA file – If you want to upload your DNA file to another vendor for matching at their site (MyHeritage and FamilyTreeDNA,) you’ll need to download your raw data file from the vendor where you tested. I provided step-by-step instructions for this process at each of the vendors, here.

DNA Segment File – This file contains the segment information with each of your matches, including the start and end locations of your matching segment(s), the total number of matching (shared) centiMorgans (cM) above the vendor’s matching threshold, and sometimes the longest segment.

If you want to sort a spreadsheet to look for all of your matches on specific areas of chromosomes, this is the best way to achieve that goal. I use this information at DNAPainter when painting the segments of matches with whom I can identify a common ancestor.

You may be able to download filtered lists or individual match data as well, as opposed to an entire match list spreadsheet, but the methodology varies at each vendor.

Ancestry does not provide segment information at all. 23and Me combines this information with the next file.

Match List – This file will contain your list of matches along with other information about the matches which you will find genealogically helpful. I find using this file easier than viewing each match separately at the vendors when trying to obtain an overview or when searching for a particular surname in either my match list or their ancestral surnames.

I can also sort by haplogroup, for example, which can sometimes help immensely if that information is available.

Ancestry does not facilitate or allow downloading your match list. 23andMe combines this information with your matching DNA segments in one file.

Here’s a handy-dandy summary by testing vendor.

Vendor Raw DNA File DNA Segment File Match List
23andMe Yes, instructions here Yes, instructions in this article Yes, instructions in this article
FamilyTreeDNA Yes, instructions here Yes, instructions in this article Yes, instructions in this article
MyHeritage Yes, instructions here Yes, instructions in this article Yes, instructions in this article
Ancestry Yes, instructions here No, does not provide No, does not provide

I’ve written step-by-step instructions for how to download your Match List and DNA Segment file(s) at each vendor.

23andMe

Please note that 23and Me is the only vendor to limit your matches, which means you will only receive a file containing:

  • 1500 matches if you tested before the V5 chip, so before August 9, 2017, and have not established communications with matches that would have rolled off of your list otherwise. (I have 1805 matches, so have established contact with 305 that would otherwise have rolled off the end.)
  • 1500 if you tested on the V5 chip, so beginning August 9, 2017, but did not establish communications OR did not purchase the health option, OR did not purchase the yearly membership. If you established communications, those matches won’t roll off, and if you purchase the membership, the match threshold is raised. You may still need to establish contact to keep people from rolling off the larger list as well.
  • 5000-ish (23andMe doesn’t say exactly) if you tested on the V5 chip for BOTH ancestry and healthy AND purchased the yearly membership.

You will only receive match information for people who are listed on your restricted match list, not people who have rolled off as closer matches arrived. Therefore, I encourage you to retain your old match lists because some of your matches will be gone each time you download.

23andMe combines your match list with your segment file.

Sign on and select DNA Relatives on the toolbar.

Next, select “See all relatives.”

Scroll to the very bottom and click on Request DNA Relatives Data Download.

Your file will be prepared, and you’ll receive an email when the file is ready to be downloaded. Mine only took a minute or two, and I simply waited on my 23andMe page until the message appeared.

Save and open the downloaded file, and you’ll see a variety of information about each of your matches, in closest-match-first order, including:

  • Match name
  • Chromosome segment match information, including start and end locations, genetic distance (centiMorgans cMs,) and SNPs
  • Maternal and paternal sides if your parent or parents have tested
  • Number of matching segments
  • Relationship information
  • Birth year
  • Percent shared DNA
  • Haplogroups
  • Notes you’ve made
  • Family surnames
  • Family locations
  • 4 Grandparents’ birth country
  • Family Tree URL, external to 23andMe, if provided by tester

FamilyTreeDNA

At FamilyTreeDNA, your match list and segment information are contained in two separate files.

Sign on and click on Family Finder Matches under Autosomal DNA Results and Tools.

You’ll see your matches. At the top of your match list, on the right side, click on “Export CSV.”

You can select “All Matches” or “Filtered Matches.”

If you haven’t selected a filter, you won’t be able to make that selection. Generally, you want the entire match list.

Your match list will be prepared and downloaded.

You’ll find:

  • Match name
  • Relationship information
  • Shared DNA total
  • Longest segment
  • Linked relationship if you have linked that person to their profile card in your tree
  • Ancestral surnames
  • Haplogroups if tested
  • Notes you’ve made
  • Bucketing – Paternal, maternal, both, none
  • X-Match amount

Note – If you’re a male, valid X matches (meaning matches that are not identical by chance,) will always be on your maternal side because you received your Y chromosome from your father instead of a copy of his X. I wrote about X matching, here.

If your match is a male, an X match will always be through his mother’s line.

Segment information is available in a separate download on the chromosome browser page.

Under Autosomal DNA Results and Tools, click on the Chromosome Browser.

You’ll be able to select people to compare in the chromosome browser, but to download all of your matching segments to all of your matches, click on “Download All Segments.”

If you select people to compare your relationship, and then click on “Download Segments,” you’ll only be downloading the segments for the people you are comparing.

To download all of your segments, be sure the “All” is showing in the link and download before selecting anyone for comparison.

MyHeritage

MyHeritage also provides two separate files for matches and chromosome segment information.

Select DNA matches, then the 3-dot menu, then “Export DNA Matches.”

If you also want your individual segment information for your matches, also order the second file on that menu, “Export shared DNA segment info for shared DNA matches.”.

You’ll see a message that your report is being prepared and will be sent to the email address on file.

If your file doesn’t appear in your email box, check your spam folder.

Your match list provides:

  • Match name
  • Age
  • Country
  • Contact link
  • DNA managed by (if not the tester)
  • Contact link for DNA manager
  • Relationship information
  • Total cM
  • Percent of matching DNA
  • Number of matching segments
  • Largest segment
  • Has tree and tree manager
  • Number of people in their tree
  • Tree link and link to contact tree manager
  • Number of SmartMatches
  • Shared ancestral surnames
  • All ancestral surnames
  • Notes you’ve made
  • Has Theory of Family Relativity

Now that you have these files, what do you do with them?

Evaluating

Is there anything that stands out as remarkable, perhaps that you didn’t know or notice before? Patterns that might be informative?

I had a huge brick wall on my mother’s side that has since fallen, but retrospectively, had I reviewed these lists when that wall was still standing firm, there was a huge hint just waiting for me.

My mother has a very unexpected Acadian line through her great-grandfather, Anthony Lore, so 12.5% of her heritage.

On my match list, I see a large number of French surnames, but I didn’t know of any French ancestors on either side of my tree. Many surnames repeat, such as LeBlanc, d’Entremont (which is really unusual), Landry, and deForest. Why were these people on my match list? This is definitely smoke, and there must be fire someplace, but where?

Looking at the locations associated with these matches’ ancestors would have provided additional clues.

However, simply googling my great-grandfather’s surname in combination with those French surnames I listed above produced these 3 top search results.

Yes, you guessed it. Anthony turned out to be “Antoine” and Lore is spelled in a variety of ways, including Lord. His family is Acadian.

That’s Anthony Lore, which is how he was listed on the death certificate of his son, in the software on my computer, above, and here is Antoine Lore at WikiTree, below.

As you can see, that brick wall falling opened a whole new group of ancestors, and along with it, my appreciation of endogamy😊

Match lists facilitate viewing the big picture and can be a very useful tool for people seeking unknowns or trying to group people together in a variety of ways.

Do you have any brick walls that need to fall?

How can or do you utilize your match lists?

_____________________________________________________________

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I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

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DNA-eXplained Celebrates Tenth Anniversary!

This blog, DNA-eXplained, is celebrating its 10th anniversary today. How time flies!

I never thought for a minute about a 10th anniversary when I launched that first article.

I started blogging to teach people and literally “explain” about genetic genealogy – which is why I selected the name DNA-eXplained. Over time, it has also been nicknamed DNAeXplain, which is fine.

I hoped to be able to answer questions once, with graphics and examples, instead of over and over again off-the-cuff. I needed someplace where people could be referred for answers. Blogging seemed like the perfect medium for achieving exactly that.

Blogs allow writers to publish content attractively and react to changes and announcements quickly.

Blogs encourage readers to subscribe for email delivery or use RSS reader aggregation and can publish to social media.

Content can be located easily using browser searches.

Everything, all content, is indexed and searchable by keyword or phrase.

Blogging certainly seemed like the right solution. Still, I was hesitant.

I vividly remember working at my desk that day, a different desk in a different location, and anguishing before pressing the “publish” button that first time. Was I really, REALLY sure? I had the sense that I was sitting in one of those life-defining fork-in-the-road moments and once embarked upon, there would be no turning back.

I’m so glad I closed my eyes and pushed that button!

I knew we were going to be in for an incredible journey. Of course, I had no idea where that roller coaster ride was going, but we would be riding together, regardless. What a journey it has been!

A decade later, I’ve had the opportunity to meet and become friends with so many of you, both online and in person. I’ve met countless cousins I never knew I had, thanks to various blog articles, including the 52 Ancestors series which has turned out to be 365 and counting.

I am incredibly grateful for this opportunity! I thought I was giving to others, yet I’ve been greatly enriched by this experience and all of you.

So much has changed in all of our lives.

Looking Back

Today, as I look back at that very short first article, I can’t help but think just how unbelievably far we’ve come.

There was one Y and mitochondrial DNA testing vendor in 2012, FamilyTreeDNA, and that’s still the case today.

There were three autosomal testing companies, 23andMe, FamilyTreeDNA, and Ancestry, in addition to the Genographic Project, which was sunset in 2019 after an amazing 15-year run. GEDmatch was two years old in 2012 and had been formed to fill the need for advanced autosomal matching tools. In 2016, MyHeritage joined the autosomal testing market. All of those companies have since been acquired.

In 2012, FamilyTreeDNA broke ground by accepting uploaded DNA files from other vendors. Autosomal DNA tests cost about $300 although prices were dropping. I don’t anticipate prices dropping much further now, because companies have to maintain a reasonable profit margin to stay in business.

In 2013, when DNA-eXplained celebrated its first anniversary, I had published 162 articles.

That first year was VERY busy with lots of innovation occurring in the industry. You can read my end-of-year article, 2012 Top 10 Genetic Genealogy Happenings if you’d like to reminisce a bit. For comparison, here’s my Genetic Genealogy at 20 Years summary.

The World is Our Oyster

In the past decade, I’ve penned articles in a wide variety of locations, in several countries, on 5 continents.

I’ve written in my offices, of course, but also in cars, on buses, trains, and planes. I’ve crafted several articles on ships while cruising. In fact, writing is one of my favorite “sea-day” things to do, often sitting on deck if it’s a nice day.

I’ve written in cemeteries, which shouldn’t surprise you, on the hood of my car, and cross-legged on the floor at innumerable conferences.

I’ve composed at picnic tables and in countless hotel lobbies, libraries, laboratories, restaurants, and coffee shops. And, in at least 3 castles.

I’ve written while on archaeology digs, balancing my laptop on my knees while sitting on an inverted bucket, trying to keep dirt, sand, and ever-present insects away.

I’ve even written in hospitals, both as a visitor and a patient. Yea, I might not have told you about that.

I’ve pretty much taken you with me everyplace I’ve gone for the past decade. And we are no place near finished!

Today

This article is number 1531 which means I’ve published an article every 2.3 days for a decade. Truthfully, I’m stunned. I had no idea that I have been that prolific. I never have writer’s block. In fact, I have the opposite problem. So many wonderful topics to write about and never enough time.

A huge, HUGE thank you to all of my readers. Writers don’t write if people don’t read!

DNA-eXplained has received millions and millions of views and is very popular, thanks to all of you.

There have been more than 48,000 comments, 4,800 a year or about 13 each day, and yes, I read every single one before approving it for publication.

Akismet, my spam blocker only reports for 45 months, but in that time alone, there have been about 100,000 attempted SPAM comments. That equates to about 75 each day and THANK GOODNESS I don’t have to deal with those.

WordPress doesn’t count “pages,” as such, but if my articles average 10 pages each, and each page averages 500 words, then we’re looking at someplace between 7 and 8 million words. That’s 13 times the size of War and Peace😊. Not only do I write each article, but I proofread it several times too.

Peering Into the Future

Genetic genealogy as a whole continues to produce the unexpected and solve mysteries.

Tools like triangulation in general, Family Matching at FamilyTreeDNA, genetic trees at 23andMe, Theories of Family Relativity at MyHeritage, and ThruLines at Ancestry have provided hints and tools to both suggest and confirm relationships and break through brick walls.

Ethnicity chromosome painting at both 23andMe and FamilyTreeDNA help unravel ancestral mysteries, especially for people with combinations of fundamentally different ancestries, as does Genetic Communities at Ancestry and Genetic Groups at MyHeritage.

Third-party tools that we love today weren’t even a twinkle in a developer’s eye in 2012. Products like DNAPainter, Genetic Affairs, and DNAGedcom pick up where the vendors leave off and are widely utilized by genealogists.

I hope that all of our vendors continue to invest in product development and provide the genetic genealogy community with new and innovative tools that assist us with breaking down those pesky brick walls.

Primarily, though, I hope you continue to enjoy your genealogy journey and make steady progress, with a rocket boost from genetic testing.

The vendors can provide wonderful tools, but it’s up to us to use them consistently, wringing out every possible drop. Don’t neglect paternal (male surname) Y DNA and matrilineal mitochondrial DNA testing for people who carry those important lines for your ancestors. All 4 kinds of DNA have a very specific and unique genealogical use.

I encourage you to test every relative you can and check their and your results often. New people test every single day. You never know where that critical piece of information will come from, or when that essential puzzle piece will drop into place.

Be sure to upload to both FamilyTreeDNA and MyHeritage (plus GEDMatch) so you are in the database of all the vendors. (Instructions here.) Fate favors the prepared.

Thank You!!

Thank you from the bottom of my heart for supporting me by reading and sharing my articles with your friends, organizations, and family members, by purchasing through the affiliate links, by buying my book, and by graciously sharing your own experiences.

Thank you for your suggestions and questions which plant the seeds of new articles and improvements.

I hope you’ve made progress with your research, unraveled some thorny knots, and that you’ve enjoyed this decade as much as I have. Tell me in the comments what you enjoyed the most or found most useful?

Here’s to another wonderful 10 years together!

___________________________________________________________

Follow DNAexplain on Facebook, here or follow me on Twitter, here.

Share the Love!

You’re always welcome to forward articles or links to friends and share on social media.

If you haven’t already subscribed (it’s free,) you can receive an email whenever I publish by clicking the “follow” button on the main blog page, here.

You Can Help Keep This Blog Free

I receive a small contribution when you click on some of the links to vendors in my articles. This does NOT increase the price you pay but helps me to keep the lights on and this informational blog free for everyone. Please click on the links in the articles or to the vendors below if you are purchasing products or DNA testing.

Thank you so much.

DNA Purchases and Free Uploads

Genealogy Products and Services

My Book

Genealogy Books

Genealogy Research