DNA Beginnings: Matching at Ancestry and What It Means

This is the fourth in the series of “DNA Beginnings” articles. Previous articles you might enjoy include:

Why Is Matching Important?

For genealogists, DNA matching to other people is the key to verifying your ancestors, beginning with your parents and continuing up your tree. You can also meet new cousins who may have information, including photos, that you don’t.

Each of the four major vendors has benefits that the others don’t have. As we review matches at each vendor, we’ll discuss the plusses and minuses of each one and how to use their unique features to benefit your genealogy quest.

Let’s start with Ancestry.

Ancestry

The highest total number of people have tested their DNA with Ancestry, although I’m not certain that holds true for testers outside the US.

This means that you are likely to find at least some close matches at Ancestry. Every vendor has people in their database that no other vendor has though. I recommend testing at the 4 major vendors, including FamilyTreeDNA, MyHeritage, and 23andMe.

At Ancestry, Where Are My Matches?

You’ll find the list of people who match you under the “DNA”, then “DNA Matches” tabs at Ancestry.

Ancestry packs a lot of information into your match pages. Let’s take a look at what that means to you as a genealogist and how you can make it work for you.

Clcik to enlarge images

I’ll be discussing each one of these areas, below, so refer back. Let’s start with the basic page arrangement.

  • Features at the top apply to managing and working with all of your matches
  • Features under each match apply to that match only.

Pretty straightforward.

I’ll begin at the top and review each item, but first, let’s talk about testing your parents.

Test Your Parents

First, if you have either or both parents available to test, by all means, test both parents and not just at Ancestry. This is sage advice for all vendors.

Be aware that if one or both of your parents are not your biological parents, DNA testing will reveal that fact.

When your parent tests, matches that Ancestry can automatically attribute to that parent’s side of your family based on matching you and your parent, both, are noted as such.

While this is useful, especially since maternally and paternally assigned matches are your closest matches, Ancestry only automatically assigns about as many matches as fall into your close matches category. Someplace between half and 1% of your total matches. I sort of deflated like a balloon when I made that discovery. 

It’s still definitely worth testing your parents, though, because you will be able to view your matches to see if they match you and a parent both. Even if Ancestry doesn’t assign them maternally or paternally, you can certainly derive clues from who you match in common – and you can assign matches yourself.

We will talk about exactly how to do this in a bit!

Now, back to the function bar.

The Function Bar

The function bar beneath the ad promoting parental testing is your driver’s seat.

Click to enlarge images

You’ll find a variety of filters and functions like searching and sorting your matches. In other words, these are the actions you can take. Let’s start with the filters, on the left.

  • Unviewed – The “Unviewed” filter widget displays only matches you have not yet viewed. Unviewed matches are annotated with a blue dot. Because your matches are displayed in highest to lowest order, you’ll see your closest unviewed match first. I use this filter a lot because it means I don’t have to scroll through the matches I’ve already viewed and analyzed.

I have a “one initial touch” policy. When I initially view a match, I step through all the functions I can utilize to identify how that person is (potentially) related to me and I make notes.

The rest of these filters and functions are important steps in that analysis process.

Please notice that you can combine filters.

I’ve clicked both the “Unviewed” and the “Common Ancestors” filters, meaning BOTH of these filters are simultaneously functioning. If you just want one filter, be sure to “Reset Filters” before clicking a second filter button.

  • Common Ancestors – That infamous little green leaf. In this case, when viewing DNA matches, that green leaf is very important because it indicates that Ancestry has found a (potential) common ancestor between you and your match.

Clicking on the little green leaf shows you the most recent common ancestor(s) that Ancestry believes you share with that match based on:

  1. The fact that your DNA does match
  2. And that you have common ancestors either in your tree
  3. Or ancestors that can be linked to both of you through other people’s trees

Notice Ancestry’s careful wording about these potential ancestors. Megan “could be” my 5th cousin once removed. “Could be.” Ancestry isn’t using weasel words here, but trying to convey the fact that people’s genealogy, Megan’s, mine or other peoples’ can be wrong.

In other words, Ancestry has found a potential link between me and Megan, but it may not be valid. These connections use trees to suggest common ancestors and some trees are not reliable. It’s up to me (and you) to confirm that suggested ancestral path.

Clicking on “View Relationship” takes me to the Ancestry tool known as ThruLines which shows me how Megan and I may be related.

I have Stephen Miller in my tree, but not his son John J. Miller as indicated by the hashed boxes.

I can click on the Evaluate button to see what type of evidence and which trees Ancestry used to assign John J. Miller as the son of Stephen Miller. In other words, I can accumulate my own evidence to validate, verify, or refute the connection to Daniel Miller for me and Megan.

I wrote about ThruLines here and here.

  • Messaged – The “Messaged” filter button shows matches I’ve sent messages to through Ancestry’s messaging feature.

You can track your messages in the little envelope button by your name at upper right.

  • Notes – The “Notes” filter shows your matches and the notes you’ve made about that match. I use notes extensively so I don’t replow the same field.

In my case, I took a second test at Ancestry several years ago when they introduced a new chip to compare to the results of my original test. I noted that this is my V2 test in this example.

Normally my notes are genealogy-related, especially in cases where I’ve discovered more than one set of common ancestors through multiple lines. I record hints here, such as which of my closest relatives this person also matches. I also record our common ancestor when I identify who that is or even who it might be.

You can create a note by clicking on the match, then on “Add Note” near the top.

  • Trees – The “Trees” filter provides the ability to view matches who have only specific tree statuses.

Perhaps you only want to view only people with public, linked trees. Why are public, linked trees important?

Public trees can be seen and searched by your matches. Private trees cannot be seen by matches.

A public, linked tree means that your match has linked their DNA test to their own profile card in a public tree. The linking process tells Ancestry who “they are” in their tree and allows Ancestry to begin searching from that person up their tree to see if they can identify common ancestors with their matches. In other words, linking allows Ancestry’s tools to work for you and allows other people to view your position in your tree so that can see how you might share ancestors.

Some people don’t understand the linking process, so I normally take a look at unlinked trees too, especially if the person only has one tree.

Be sure your DNA test is linked to your tree by clicking on the little down arrow by your user name in the upper right-hand corner of the screen, then, click on “Your Profile,” then click on the settings gear beneath your name.

Then click on DNA:

You’ll see the tests that you own, so click on the little right arrow (>) to work with a specific test.

Finally, you’ll see the name on the test, the profile it’s connected to, and the name of the tree.

Not accurate or what you want? You can change it!

Ok, back to working with filters. Next, Shared DNA.

  • “Shared DNA” allows you to view only specific relationships of matches.

I use this tab mostly to see how many matches I have.

  • The “Groups” filter categorizes matches by the colored dot groups you establish. Matches can be assigned to single or multiple groups.

The good news is that you have 24 colored dot buttons that represent groups to work with. The bad news is that you have only 24 that you can assign.

Generally, I assign colored dots, and therefore matches, to a couple, not an individual. In some cases, especially with two marriages, I have assigned match buttons to a single ancestor. Of course, that means that one couple uses 2 colored buttons☹

After you’ve created your groups, you can assign a match to a group, or multiple groups, by clicking on your match.

“Add to group” is located right beside “Add note,” so I do both at the same time for each match.

I have one group called “Ancestor Identified” which is reserved for all ancestors who don’t have colored group dots assigned. I can tell which ancestor by reading the notes I’ve entered.

To view every match in a particular group, click on that group, then “apply” at the bottom.

The matches displayed will only be the 17 matches that I’ve assigned to the blue dot group – all descended from Antoine Lore (and his wife).

However, looking at who I match in common with these 17 people can lead me to more people descended from Antoine, his wife, or their ancestors.

  • Search – The “Search” function at far right allows you to search your matches in multiple ways, but not by the most important aspect of genealogy.

  1. You can search by the match’s name; first, last or Ancestry user name.
  2. You can search by surname in your matches’ trees. I sure hope you don’t have Jones.
  3. You can search by birth location in matches’ trees.
  4. You CANNOT search by ancestor. Say what???

Seriously.

Come on Ancestry…don’t make this intentionally difficult.

  • “Sort” allows you to sort your match list either by relationship (the default) or by date. I’d trade this for search by ancestor in a New York Minute.

We are finished with the filters and functions for managing your entire list, so let’s see what we can do with each individual match.

Match Information

We’ve already learned a lot about our matches just by using different filters, but there’s a lot more available.

You’ll need to click on various areas of the match to view specific or additional information.

Click on the predicted relationship, like 5th-8th cousin, to view how closely Ancestry,  thinks you are related based on the amount of DNA you share. If you click on the relationship, Ancestry displays the various relationship possibilities and how likely each one is.

Looks like there’s a bit of a disconnect, because while Ancestry predicts this relationship with 17 shared cM of DNA at 5th-8th cousin, their chart shows that variations of 3rd or 4th cousin are more likely. This is a great example of why you should always click on the predicted relationship and check for yourself.

Conversely, if you’re related to a match through multiple lines, or through one set of ancestors more than once, Ancestry may predict that you are related more closely than you actually are – because you may carry more of that ancestor’s DNA. Ancestry, nor any other vendor, has any way of knowing why you carry that amount of ancestral DNA.

Ancestry also shows you a little more information about how much DNA you share, and how many segments. Unfortunately, Ancestry does not provide a chromosome browser, so there isn’t any more you can do, at Ancestry, with this information – although you can certainly transfer your DNA to MyHeritage, FamilyTreeDNA, or GedMatch (a third-party tool) who all provide chromosome browsers.

Ancestry shows you the number of cMs, or centiMorgans of DNA you share. Think about a centiMorgan as a length measure, for practical purposes. Each vendor has their own matching threshold and a matching piece of DNA with another person must be larger than that bar. Ancestry’s minimum cM threshold is 8 cM, the highest of all the vendors.

This means that any match lower than 8 cM is not considered a match at Ancestry, but that same person might appear on your match list at another vendor whose match threshold is lower.

Ancestry also removes some of your matching DNA before considering matches. In areas where your DNA is “too matchy,” Ancestry removes some segments because they feel that DNA may be “older” and not genealogically relevant.

There’s a great deal of debate about this practice, and strong feelings abound. Some people feel this is justified because it helps reduce the large number of matches, especially for people who descend from highly endogamous populations.

Other people who have one endogamous line among many others find that many or most of their matches from that population were removed by Ancestry when they did one of their two purges. That’s what happened to my Acadian and many of my African American matches.

Regardless, Ancestry tells you for each match if they removed DNA segments using their Timber algorithm, and if so, how many.

Clearly, when viewing this match, 1 cM of removed DNA isn’t going to make much if any difference unless that 1cM was the difference between being a match and not matching. You can read Ancestry’s paper about how their matching works beneath the hood, here.

There are only two real differences that DNA removal makes at Ancestry:

  • Whether you match or not, meaning you’re either over or under that 8 cM bar.
  • Shared matches under 20 cM won’t show, so if you have 22 cM of shared DNA with someone and Ancestry removes 3, you won’t show as a shared match to people you match in common. And people you match in common, if they have less than 20 cM shared DNA won’t show to you either.

Since Ancestry doesn’t provide their customers with advanced tools to compare segments of DNA with their matches, other than the two circumstances above, the removal of some DNA doesn’t really matter.

That might be more than you wanted to know! However, if you find some matches confusing, especially if you know two people are both matching you and each other, but they don’t show as a shared match, this just might be why. We’ll talk about shared matches in a minute.

Do Your Recognize Your Matches?

Ancestry provides a way for you to assign relationships.

If you click on “Learn more,” you’ll view the match page that shows their tree, common ancestors with you, if identified, and more.

If you click “Yes,” you’ll be prompted for how you match.

Ancestry will ask if you know the specific relationship based on the probabilities of that relationship being accurate.

After you confirm, that individual will be assigned to that parental side of your family, or both, based on your selection.

Shared Matches

Shared matches are a way of viewing who you and one of your matches both match.

In other words, if you recognize other people you both match, that’s a HUGE clue as to how you and your match are related. However, it’s not an absolute, because you could match two people through entirely different lines, and they could match each other through another line not related to you. However, shared matching does provide hints, especially if your match matches several relatives you can identify who descend from the same ancestor or ancestral couple.

This match only has initials and a private unlinked tree. That means they aren’t linked to the proper place in their tree, and their tree is private so I can’t view it to evaluate for hints.

How can I possibly figure out how we are related?

Click on the match.

Clicking on Shared Matches shows me the people that T. F. and I both match.

Notice that T. F. and I match my 5 top matches on my mother’s side. Clearly, T. F. and I share common ancestors on my mother’s side.

Furthermore, based on my notes and the amount of DNA we share, our common ancestor is probably my great-grandparents.

This match was easy to unravel, but not all are. Lets’s look at a different shared match list.

In this example, all 4 people have unlinked trees. The smallest shared match is 20 cM –  because Ancestry doesn’t show smaller shared matches below 20 cM. Of course, there are probably a lot of smaller shared matches, but I can’t see them. In essence, this limits viewing your shared matches to the 4th-6th cousin range or closer.

Just be aware that you’re not seeing all of your shared matches, so don’t assume you are.

Summary

By reviewing each match at Ancestry using a methodical step-by-step approach, there’s a great deal of information to be gleaned.

Let’s summarize briefly:

  • Your matches listed first on your match list are your closest, and likely to be the most useful to you in terms of identifying maternal and paternal sides of your family for other matches.
  • Test either or both parents if possible
  • Link yourself and the DNA kits you manage to their proper place in your tree so that Ancestry can provide you with parental sides for your matches if your parents have tested. Ancestry uses linked trees for ThruLines tii.
  • Manually assign “sides” to matches if your parents aren’t available to test.
  • Use the filters or combinations. Don’t forget to reset.
  • Click on “Common Ancestors” to view potential common ancestors – matches exhibiting those green leaves. This is Ancestry’s strength.
  • From Common Ancestors, check ThruLines to view matches linked to a common ancestor.
  • Don’t neglect unlinked trees.
  • Assign dot colors to ancestral couples or a way that makes sense to you.
  • Assign matches by colored dot group.
  • Make notes that will help you remember details about the match and what you have and have not done with or learned about that match.
  • Search by location or surname or a combination of both.
  • Assign relationships, when known. At least assign maternally or paternally, or both if the match is related through both sides of your family. Hint – your full siblings, their children, and your children are related to both sides – your mother’s and father’s sides, both.
  • Click on your match’s profile to view additional information, including common ancestors and their tree. Scroll down to view common surnames, locations and ancestors from both people (you and your match) found in those locations.
  • View shared matches to see who else you and your match are both related to. Your shared matches may well hold the key to how you and an unknown match are related. Don’t forget that Ancestry only displays shared matches of 20 cM or larger.
  • If you’d like to utilize a chromosome browser for additional insights and to confirm specific common ancestors by shared segments of DNA, download a copy of your raw DNA data file and upload, free, to both FamilyTreeDNA and MyHeritage, here. They both provide chromosome browsers and advanced tools.

You can find step-by-step instructions for downloading from Ancestry and uploading elsewhere, here.

Join Me for More!

I’ll be publishing similar articles about working with matches at FamilyTreeDNA, MyHeritage and 23andMe soon.

If you haven’t tested at all of these vendors and would like to, just click on these links for more information or to order tests:

Subscribe to this Free Blog

Did you enjoy this article?

You can subscribe to receive my articles in your email for free at www.dnaexplain.com by entering your email address and clicking on the Follow button.

Follow DNAexplain on Facebook, here or follow me on Twitter, here. You can always forward any of my articles or links to friends.

____________________________________________________________

Disclosure

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

Books

  • com – Lots of wonderful genealogy research books

Genealogy Research

DNA Beginnings: How Many DNA Matches Do I Have?

People often want to know how many DNA matches they have.

Sounds simple, right?

At some vendors, the answer to this question is easy to find, and at others, not so much.

How do you locate this information at each of the four major vendors?

What else do you need to know?

I’ve written handy step-by-step instructions for each company!

Matches at FamilyTreeDNA

Sign on at FamilyTreeDNA and under autosomal results, click on Family Finder Matches.

At the top of the next page, you’ll see your total number of matches along with matches that FamilyTreeDNA has been able to assign maternally or paternally based on creating/uploading a tree and linking known matches to that tree in their proper place.

Your parents do NOT need to have tested for the maternal/paternal bucketing functionality, but you DO need to identify some relatives and link their tests to their place in your tree. It’s that easy. Instructions for linking can be found in the “Linking Matches on Your Tree” section of this article (click here), along with information about how that helps you, or here.

Obviously, if your parents have tested, that’s the best scenario. For people who don’t have that option, FamilyTreeDNA is the ONLY vendor that offers this type of feature if your parents have NOT tested.

At FamilyTreeDNA, I have 7313 total matches of which 3169 are paternal, 1402 are maternal and 6 are related to both parents.

Hint – your siblings, their children, your children, grandchildren, etc. will be related to you on both your paternal and maternal sides.

If you don’t have an autosomal DNA test at FamilyTreeDNA, you can upload one from Ancestry, 23andMe, or MyHeritage for free. Click here for instructions.

Matches at MyHeritage

At MyHeritage, sign on and click on DNA, then DNA Matches.

At the top of your matches page, you’ll see your total number of matches.

At MyHeritage, I have 14,082 matches.

Matches are not broken down maternally and paternally automatically, but I can filter my matches in a wide variety of ways, including shared matches with either parent if they have tested, or other relatives.

If you don’t have an autosomal DNA test at MyHeritage, you can transfer one from Ancestry, 23andMe, or FamilyTreeDNA for free. Click here to begin your upload to MyHeritage.

Click here for instructions about how to download a copy of your DNA file from other vendors.

Matches at Ancestry

At Ancestry, sign on and click on DNA, then DNA Matches.

On your matches page, at the top, you’ll see a number of function widgets. Look for “Shared DNA.”

Click the down arrow to expand the Shared DNA box and you’ll see the total number of matches, along with the breakdown between 4th cousins or closer and distant matches.

Sometimes the number of matches doesn’t show up which means Ancestry’s servers are too busy to calculate the number of matches. Refresh your screen or try again in a few minutes. This happens often to me and always makes me question my sanity:)

I have 53,435 matches at Ancestry, of which 4,102 are estimated to be 4th cousins or closer and 49,333 are more distant.

For close matches only, if your parents have tested at Ancestry, when possible, Ancestry tells you on each match if that person is associated with your father’s side or your mother’s side.

You can’t upload DNA files from other vendors to Ancestry, but you can download a copy of your DNA file from Ancestry and upload to either FamilyTreeDNA or MyHeritage. Click here for instructions.

You can also download a copy of your tree from Ancestry and upload it to either of those vendors, along with your DNA file for best results.

Matches at 23andMe

23andMe functions differently from the other vendors. They set a hard limit on the number of matches you receive.

That maximum number differs based on the test version you took and if you pay for a membership subscription that provides enhanced medical information along with advanced filters and the ability to have a maximum of 5000 matches.

In order to purchase the membership subscription, you need to take their most current V5 test. If you tested with an earlier product, you will need to repurchase, retest or upgrade your current test which means you’ll need to spit in the vial again.

Please note the words, “up to 5000 relatives,” in the 23andMe verbiage. They also say that’s “over 3 times what you get” with their test without a subscription.

23andMe handles things differently from any other vendor in the industry. They made changes recently which created quite a stir because they removed some capabilities from existing customers and made those functions part of their subscription model. You can read about that here and here.

The match limit on the current 23andMe V5 test, WITHOUT the subscription, is 1500. If you tested previously on earlier kits, V2-V4, 23andMe has reinstated your prior maximum match limit which was 2000.

So, here’s the maximum match summary for 23andMe:

  • Earlier kits (V2-V4) – 2000 maximum matches
  • Current V5 kit with no subscription – 1500 maximum matches
  • Current V5 kit with subscription – 5000 maximum matches

Except, that’s NOT the number of matches you’ll actually see.

23andMe handles matching differently too.

23andMe matches you with their other customers up to your maximum, whatever that is, then subtracts the people who have not opted-in to genealogy matching. Remember, 23andMe focuses on health, not genealogy, so not all of their customers want matching.

Therefore, you’ll NEVER see your total number of allowed matches, which is why 23andMe cleverly says you “get access to up to 5000 relatives.”

Let’s look at my V4 test at 23andMe. Sign on and click on Ancestry, then DNA Relatives. (Please note, Ancestry is not Ancestry the company, but at 23andMe means genealogy results as opposed to medical/health results.)

At the top of your DNA Relatives page, you’ll see your total number of matches, before any sorting filters are applied.

23andMe does not automatically assign matches maternally or paternally, but if your parents have tested AND opt-in to matching, then you can filter by people who also match either parent.

I have 1796 matches at 23andMe, which means that 204 or 11% of my matches have not opted-in to matching.

You can’t upload DNA files from other vendors to 23andMe, but you can download a copy of your DNA file from 23andMe and upload to either FamilyTreeDNA or MyHeritage where you will assuredly receive more matches. Click here for instructions.

Summary

Each vendor has its own unique set of features and operates differently. It’s not so much the number of matches you have, but if you have the RIGHT match to break through a particular brick wall or provide you with a previously unknown photo of a cherished family member.

I encourage everyone to fish in all 4 of these ponds by testing or uploading your DNA. Uploading and matching are both free. Advanced tools require a small one-time unlock fee, but it’s significantly less than testing again. You can find step-by-step instructions to walk you through the process, here.

Have fun!!!

_____________________________________________________________

Disclosure

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 Transfers

Genealogy Products and Services

Books

Genealogy Research

DNA Beginnings: What is a Match?

Before we evaluate matches at each of the four major vendors, FamilyTreeDNA, MyHeritage, Ancestry and 23andMe, let’s discuss what a DNA match is, what it means, and what it does NOT mean.

A Match to Another Person

Each of the four major vendors, but not some other vendors, provide matches to you and other individuals in their database.

This example from FamilyTreeDNA shows my mother’s match list listing me as her closest match, along with a kit I uploaded from Ancestry when I was recently updating upload/download article instructions for my readers. You don’t need to upload multiple kits to vendors.

Every vendor’s match list looks different, as is the information they provide. We will cover each vendor’s match list individually in future articles in this DNA Beginnings series.

Each vendor has different criteria for matching, but in essence, using that vendor’s match criteria – your DNA and the DNA of a person you match are identical on a section of DNA of a vendor-defined length.

Each of those vendors identifies the people who match each other and opt-in to matching in one way or another,

When you sign on to your account at each vendor, you’ll see a match list. Each of those people on that list match your DNA:

  • At or above the vendor-defined centiMorgan (cM) threshold. You can read more about centiMorgans here.
  • At or above the vendor-defined SNP threshold, meaning the number individual contiguous matching locations.

Each vendor has their own thresholds and internal algorithms that define matches. For example, a match of 8 cM with 1500 SNPs refers to both the length of the match (cM) and the density of locations within that segment of DNA that match between two people. Only matches above each vendor’s threshold appear on your match list.

Matches smaller than or beneath those vendor thresholds are considered less likely to be valid matches, so are excluded and do not appear on your match list.

Imputation Affects Matching

Different vendors test their customers’ DNA on different DNA chips:

  • Different chips test a different amount of DNA, but generally roughly 700,000 SNP locations
  • That 700K locations of DNA can be in different locations in your genome

In other words, just because two vendors both test 700,000 locations doesn’t mean they test the same 700,000 locations.

Even the same vendor will, over time, implement different DNA testing chips or modify the SNP locations tested on the same chip.

These different chips, chip versions and SNP locations are not fully compatible with each other, so the vendors use a technique known as imputation to level the playing field between non-identical files.

This is particularly relevant for vendors that accept uploads from other vendors.

In this example, we have 3 vendors and 10 different SNPs, or DNA locations.

  • Vendor 1, on their first Version 1 chip, tested locations 1-8.
  • Vendor 1, on their second V2 chip, tested locations 3-10.

Therefore only 6 locations, 3-8, were “common” between those two different chips used by the same vendor.

  • Vendor 2, on yet a different DNA testing chip version (V3) tested locations 1-4 and 7-10.
  • Vendor 3 on chip version V4 tested locations 2-5, 7, 8 and 10.

There are only 4 locations out of 10 tested by all the vendors’ chips.

If the vendor’s match criteria is that 10 locations in a row must match, then none of these people will match each other.

Sometimes differences occur because of chip differences, and sometimes a difference occurs because a location doesn’t read well for some reason.

In order to compensate for the differences in DNA locations tested/reported, a technique called imputation is widely used.

Imputation uses scientific probability techniques to fill in the blanks based on DNA that typically neighbors or “travels with” the nucleotides or DNA values, (T, A, C or G), found in the customer being tested.

Imputation allows all of those blanks to be filled in for all customers for each of those 10 locations, assuming the “missing DNA” is close to tested DNA locations.

It’s thanks to imputation that customers can download their raw DNA files from one vendor and upload to another for matching, even though the vendors don’t use the same exact chip.

Sometimes imputation is incorrect. Matching can be affected in both directions, meaning that some people will be on each other’s match lists who actually don’t match on a particular segment. Others would actually match if all of those locations were tested.

The highest quality matches are between people who tested at the same vendor, on the same chip or at two different vendors who use exactly the same chip. However, that’s often not possible and isn’t within the control of the customer.

False Positive Matches

This translates to, “You’re a match but not really” and is a headache for genealogists.

False positive matches show as a match between two people on their match lists, but they aren’t actually valid matches for genealogy.

  • A false positive match could occur as a result of imputation, of course.
  • A false positive match could also occur because the two people match because part of the DNA of their mother and part of the DNA of their father at those locations just happens to combine to appear as a match.

For purposes of these examples, presume that each of these matches exceeds the vendor’s match criteria so would be shown on your match list.

In our example, Person 1 and Person 2 match at all 10 locations, so they would appear on each other’s match lists.

However, if we could see the DNA of Person 2’s parents, we would see that Person 2 DOES match Person 1, but is NOT a valid match. Person 3 inherited the first 5 DNA locations from their mother and the second 5 DNA locations from their father.

While Person 2 technically is a match to Person 1, they aren’t a legitimate match because the segment of DNA that matches does not descend from the same parent. This means that the DNA did not descend in one piece from ONE ancestor, but clearly descended in pieces from two ancestors – one maternal and one paternal.

Therefore a technical match that is not a genealogical match because the DNA is inherited in part from both parents is known as a false positive and is said to be Identical by Chance, or IBC. You can read about IBC matches here.

False Negative Matches

A false negative match is just the opposite. False negatives occur when two people are NOT reported on each other’s match lists when they actually would match if all of the DNA at the various required locations were tested, read, and reported accurately. In other words, if imputation were not necessary.

  • False negatives can be caused by imputation not working as accurately as we would hope. Imputation is a probability tool, and it’s not perfect.
  • False negatives can also be caused by differing match thresholds at different vendors.

For example, if one vendor reports matches at 6 cM and above, and a second vendor reports matches at 8 cM and above, the same two people who match at 7 cM will match at the first vendor, but not at the second.

The only way you would ever know about a false negative match, because they aren’t reported, is if you simply happen to match at a vendor who allows smaller thresholds.

Also, keep in mind that each vendor creates their own imputations algorithms, so two different vendors using imputation on the same file may produce different results.

Determining Valid Matches

So, how might you determine which matches are actually valid matches?

That’s a great question.

There are useful “hints:”

  • If your parents have tested, a valid match will match one of your parents on that same segment of DNA. If your match does NOT match one of your parents, it’s a false positive match and invalid for genealogy.
  • If only one of your parents has tested, and your match does NOT match the tested parent, you can’t presume that person automatically matches your other, non-tested parent. That match could match your non-tested parent, or could be IBC.
  • If neither of your parents have tested, check to see if your match also matches close relatives who have tested, but not your descendants. For example, if a match also matches your aunt or uncle, or first cousins, that increases the probability that the match is probably valid.
  • The larger the match, the more likely it is to be a valid match. For example, matches in the 6-7 cM level are IBC about half the time. By the time you’re evaluating matches at the 20 cM level for a single segment, they are accurate almost all the time.

Keep in mind that each matching segment must be confirmed separately, and not every vendor shares the locations of the segments that match.

So What Is a Match?

  • A match is a person who is found on your match list at one of the major vendors.
  • A match at one vendor may not be on your match list if you both have DNA at another common vendor due to various reasons including the vendor’s match criteria, imputation, or file compatibility issues.
  • A match may be false positive, or IBC which means that person is not an accurate match for genealogy. This is especially true for smaller segment matches.
  • A false positive match can occur because of erroneous reads, imputation, or because your match is identical by chance.
  • The larger a matching segment of DNA, the more likely it is to be an accurate match meaning you and your match share a common ancestor.
  • The best way to tell if your match is valid is to compare your match to both of your parents as well.

A match is not a guarantee that you share a common ancestor unless you are matching to close relatives. You won’t match a close relative if the match is not valid.

What About You?

What is your plan to verify that your matches are valid?

Have your parents tested their DNA? Either of both parents?

If so, ask for your parents to upload their DNA with you to each vendor where you upload your own results.

At each vendor, you’ll have different matches. That’s exactly why we fish in multiple ponds.

I always work with my closest matches first, because I’m the most likely to be able to easily identify our common ancestor.

Locate your closest known relatives from both your mother’s side and your father’s side at each vendor. These people will be extremely helpful for our next article about shared matches.

_____________________________________________________________

Disclosure

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 Transfers

Genealogy Products and Services

Books

Genealogy Research

Announcing DNA Beginnings – A New Series

Welcome to DNA Beginnings. This exciting, upcoming series will be focused on the new DNA tester who may also be a novice genealogist and is unsure of quite what to do.

People ask, “Where do I even start?”

If this is you, welcome!

Which Vendors Will Be Covered?

This series will consist of one article for each of the four main DNA vendors:

Topics

Each article will cover two primary topics:

  • Matches
  • In-common-with or shared matches between you and other people

Along with:

  • Why each match type is important.
  • What matches and shared matches can tell you
  • How to make use of that information

More Information

For those who are ready – at the end of each article, I’ll include links with instructions for using more advanced tools at each vendor.

Get Ready!

While you’re waiting, you can upload your DNA data file from some vendors to other vendors, for free! That way you’ll have matches to work with, in multiple places. You’ll match different people at each vendor who are related to you in different ways. You never know where the match you need will be found – so fish in multiple ponds.

If you’ve tested at any vendor, you can download your raw DNA file. Downloading your raw DNA data file doesn’t affect your DNA file or matches at the vendor where you tested. The file you’re downloading is just a copy of the raw DNA file.

Just don’t delete the DNA test at the original vendor. That’s an entirely separate function, so don’t worry.

Uploading your raw DNA file to another vendor, for free, saves the cost of retesting, even if you do have to pay a small fee to utilize that vendor’s advanced tools.

Which Vendors Accept Upload Files?

Which vendors accept raw DNA data file uploads from other vendors? The chart below shows the vendors where you’ve tested on the left side, and the vendors you want to transfer to across the top.

To read this, people who have tested at FamilyTreeDNA (from the left column) can upload their raw DNA file to MyHeritage, but not to 23andMe or Ancestry. Note the asterisks. For example, people who tested at MyHeritage can upload their DNA file to FamilyTreeDNA, but only if they tested after May 7, 2019.

From to >>>>> FamilyTreeDNA MyHeritage 23andMe* Ancestry*
FamilyTreeDNA N/A Yes No No
MyHeritage Yes** N/A No No
23andMe*** V3, V4, V5 V3, V4, V5 N/A No
Ancestry V1, V2 V1, V2 No N/A

* Neither 23andMe nor Ancestry accept any DNA file uploads from any vendors. To receive matches at these two vendors, you must test there.

** FamilyTreeDNA accepts MyHeritage DNA tests taken after May 7, 2019.

*** Vendors do not accept the early 23andMe V2 file type used before December 2010.

None of these vendors accept files from LivingDNA who uses an incompatible DNA testing chip, although LivingDNA accepts upload files from other vendors.

Step-By-Step Instructions for Transferring Your Raw DNA Files

I wrote articles about how to download your raw DNA file from each vendor and how to upload your DNA file to vendors who accept DNA uploads in lieu of testing at their site.

You’ll save money by transferring your DNA file instead of testing at each vendor.

Transfer your file now and get ready to have fun with our DNA Beginnings articles!

Share and Subscribe – It’s Free

Feel free to share these articles with your friends and organizations. Anyone can subscribe to DNAexplained (this blog) for free and receive weekly articles in their inbox by entering their email and clicking on the little grey “Follow” button on the upper right-hand side of the blog on a computer or tablet screen. Hint – if you received this article in your email – you’re already subscribed so you don’t need to do anything. If you’re not subscribed already, just filling the info and click on “Follow.”

Every genealogist and genetic genealogist starts someplace and DNA Beginnings is a wonderful opportunity. The first article in the series will be arriving later this week!

_____________________________________________________________

Disclosure

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

Books

Genealogy Research