Autosomal Matchmaking Vendor Comparison

Matchmaker, matchmaker…make me a match.

Indeed, matching is what autosomal DNA for genetic genealogy is all about.  Let’s take a look at the difference between matching at the various vendors and how it affects us as genetic genealogists.

Harold is my third cousin.  We have been genealogy research partners now for about 20 years on our family lines.  Fortunately, both Harold and I have encouraged our cousins and family members to test their DNA – at all 3 testing companies.  We’ve uploaded the results to GedMatch and we’ve matched, compared and triangulated until we’re blue in the face.

Hey, it keeps us off the streets:)

What this does, however, is gives us a very firm foundation to compare results at the different companies and with different tools.

Today, I’m going to take a look at how the matches differ at the different companies and at GedMatch when comparing the same people – and how it affects us as genealogists.

First, the matching thresholds aren’t the same, but we can compensate for that and we can see how the threshold differences affect our actual matches.

The following table shows the vendor autosomal matching thresholds.

Vendor Autosomal Matching Thresholds


At 23and Me, Harold and I share a total of 133.8 cM of DNA and 21,031 SNPs spread across 6 different segments on 5 chromosomes.

Harold Me 23andMe

Family Tree DNA

At Family Tree DNA, Harold and I share 152.44 cM of DNA with 35,774 shared SNPs.

FTDNA Harold Me

Family Tree DNA reports much smaller matching segments than 23andMe and by process of inference, Ancestry.  The chart below shows Harold matching to me at Family Tree DNA.  The green overlay highlights the segments that 23andMe shows for Harold and I as matches.  The non-highlighted rows are shown at Family Tree DNA, but not at 23andMe.

Harold Me FTDNA 23andMe

Family Tree DNA does us the HUGE favor of providing all the actual matching DNA segments over 500 SNPs in length as long as we match first on a larger segment.  The other vendors remove these.


Utilizing a new private tool currently in beta test, Harold and I share 113.92 cM of DNA at Ancestry.  Of course, there is no segment data, so all we have is a total, which is certainly more than we had before.

Ancestry runs their customer’s DNA through a phasing process that eliminates many segments before they do matching.  Therefore, the significantly smaller cM total on Ancestry is a result of their phasing and matching routines.

However, by comparing the Ancestry total to the 23andMe total, which is the next most restrictive result, we can see the difference.

23andMe’s total is 133.8, so the difference between the 23andMe and the Ancestry match is 19.88 cM.  If you look at the 23andMe matches, you’ll notice that the two smallest segment matches are 10.4cM and 12.8cM and together they total 23.2 cM, with is just slightly more than the 19.88 we’re looking for.

Harold Me 23andMe Ancestry

You may have noticed already that begin and end segments and matches between vendors even on the same chromosome do vary some.  These two red segments, above, are the most likely candidates to be the missing Ancestry segments, in part, because they are the smallest and their total is near to the 19.88.


At GedMatch, comparing Harold and I at the default of 700 SNPs and 5cM, which is equivalent to the 23andMe threshold, gives us the following:

Harold Me GedMatch at 23andMe Threshold

Next, I ran GedMatch at 500 SNPs and 1cM which is the equivalent of the FTDNA threshold after you have an initial match.

Harold Me GedMatch at FTDNA threshold

Vendor Summary

I’ve put together a vendor summary of our findings.

vendor match summary2

There’s quite a difference between vendors.  More than I expected.

Comparing the Vendors

Given that the GedMatch comparison using the FTDNA thresholds is the most generous in terms of matching segments, let’s compare the three vendors matching segments against the GedMatch matching segments.  Because start and end segments aren’t exactly the same, if any portion of the vendor’s match falls into the GedMatch match segment, I’ve counted it as a match, so in favor of the vendor.

The chart below utilizes the GedMatch to FTDNA matching segments as the foundation, and I’m comparing other vendors’ matches to the GedMatch results.

All Vendor Match Comparison

For purposes of this comparison, ignore WHICH (start, end, cM) column is colored.  I’ve just selected 3 columns and assigned one to color per vendor.  If that segment row is found in that vendor’s comparison, it’s highlighted in that vendor’s color.  So, for the first row, only FTDNA reported chromosome 1, from 44,938,970 to 47,788,153 as a match.  So, therefore, their cell in that row is the only one colored with their color, green.  Looking down to chromosome 5, you can see that both FTDNA and 23andMe show those segments as matches.  Only four chromosome segments are matches using the inferred Ancestry results based on their total cM information.

How Does This Affect Matching

When Ancestry introduced their phasing, as you might recall, a great many matches disappeared.  In essence, what Ancestry has done is relieved you of the problem of figuring out which matches are “solid” by not giving you any option to work with the raw data.

One of the comments that Ancestry has made is that few people who match in a DNA Circles match on the same segments.  In other words, they don’t triangulate, which means that Ancestry is telling us we don’t need to bother with triangulation because it won’t work anyway.  Their commentary becomes more understandable if you eliminate anything but large segments.  Most people who are distantly related are NOT going to match on large segments, and an entire group is not going to match on the same large segment, which is why we desperately need those smaller segments too – along with the raw data to compare.

Of course, because Ancestry provides us with no tools, we can’t see how we match our matches.

The best we can do is to download Ancestry raw data results to either or both Family Tree DNA and GedMatch – but we’ll never see what matches we are missing at Ancestry, which is really sad.

I ran my matches at both Family Tree DNA and at GedMatch for the two segments that Ancestry has apparently removed.

Yes, I have quite a few matches on those segments.  But not beyond what would be expected in terms of the number of people in the data base that I’m being compared to.  I do have some regions that are clearly from endogamous populations, and those areas have pages and pages of matches.  These two segments aren’t like that.

At GedMatch, I ran a triangulation report of that segment of chromosome 5 where I match others at both 23andMe and Family Tree DNA.  And for the really sad part – look at all those A kits, meaning Ancestry – more than half.  Those aren’t small segment matches either.  One triangulation group that includes an Ancestry kit is 14.7cM.  I’m missing those matches at Ancestry unless I happen to match these people on a larger segment that hasn’t been removed by Ancestry’s phasing.

GedMatch Triangulation Chr 5

I decided to check the second segment that Ancestry has removed that shows as a match through23andMe, Family Tree DNA and GedMatch – on chromosome 18.  There are fewer matches on that segment of chromosome 18, not more – so it’s not a pileup area either.  It does triangulate with other people who descend from a common Vannoy ancestor who are not close relatives.

At Family Tree DNA, here are my matches to 5 known Vannoy cousins on chromosome 5 at the FTDNA default threshold.  As you can see, I match two cousins, so we have a triangulation group of 3.


Look what happens below, in terms of matching, when the match threshold is lowered.  In addition to several other matches on other chromosomes, I’ve picked up another match on that segment of chromosome 5, which serves to increase that triangulation group to four people on that segment.

FTDNA chr 5 at 1cM

I checked, and indeed, the green, blue and orange cousins do match each other on this segment as well.  Chromosome 18 triangulated too, but with different cousins matching the base person.   The orange cousin is in both triangulation groups.

FTDNA chr 18

Ancestry apparently discarded both of those segments on chromosome 5 and on 18.  Ancestry claims that seldom do people in their DNA Circles match each other on the same segments.  That’s probably true if you’re measuring only very large segments, but we can see from these examples that these are neither pileup regions nor nonmatching segments.  They triangulate between cousins, so they are valid identical by descent matches.


I ran this little test as an experiment, but I must admit, I was stunned at the disparity in the matching of the vendors.  There has been a great deal of discussion surrounding the merits of Ancestry’s phasing.  Ancestry claims they are removing non-genealogical matches, as in IBS matches by population in pileup regions.

Based on what we’re seeing above, assuming the inferred discarded segments are accurate (without additional tools, inference is as good as it gets), they’ve pruned the tree too deeply.  That’s really not apparent when you look at your matches at Ancestry for three reasons:

  • Their data base is very large, so you still have a lot of matches
  • You can’t see your segment information
  • The Ancestry matches you do have are only the strongest – so you, proportionally, will have more “solid” matches at Ancestry than at other vendors – which makes people happy who don’t understand the behind the scenes ramifications of what they AREN’T getting and that those matches are not proven to that ancestor – nor is there any way to prove the data without a chromosome browser type of tool.

The smaller the matches reported by the vendors, the further out in time it moves the bar to finding your ancestors – which is why Family Tree DNA has a larger threshold, but still reports the small matching segments.

Let me say that again, in another way.

If you used a hypothetical matching threshold of 50cM for the smallest matching segment, you’re only going to get matches to about second cousins or closer.  Harold and I wouldn’t match with our largest segment being 47cM and we very clearly share a common ancestor. You’d have very few matches (if any) BUT they would all be very solid.  You’d be able to figure out quickly how you are related.  But how would this be useful to genealogy?  You likely already know those people. So this approach is very accurate, but also very restrictive, providing no opportunity to break down those distant brick walls.

If you move the threshold out to Ancestry levels, you’re going to get more matches, but fewer further back in time because the DNA from each contributing ancestor is reduced in each generation.  The majority of your matches will be beyond the 2nd cousin level, because you have a LOT more matches with each generation you go back in time.  Still, your matches will still probably be within a few generations.

At Ancestry, I have only one 3rd cousin DNA tree match, meaning a common ancestor has been identified with that person, about thirty 4th cousins, about a hundred 5th cousins and about thirty distant cousins.  So, you can see that 5th cousins are probably your most likely match and it falls off quickly after that.

If you move the matching threshold out even further, by making it smaller, you’ll have even more matches but many will be distant.  A greater percentage will be identical by chance and identical by population, but you will have some valid matches in those smaller segments.  The caveat is of course that you would have to work to sort the wheat from the chaff, by using triangulation methods.  The common ancestor will likely not be evident and may not be identifiable.  Conversely, the common ancestor may be identifidable…and that may be just what you need to break down that long standing brick wall.  I’ve done that twice now, once on my Younger/Hart line, confirming a wife’s rumored maiden name and one in my Vannoy line, confirming Elijah’s parents through matches to his mother’s Hickerson line.

But, if you don’t have those smaller segments to work with, along with tools, you will NEVER be able to find those elusive distant ancestors using DNA.

The great irony in all of this is that while I was working with the matches to chromosome 5 for this article, I noticed a couple of new matches I hadn’t seen before.  These matches also triangulate, but are from a female line, and now I know that at least part of that segment comes from the Crumley maternal line that married into the Vannoy line.  So, of you think for one minute that these smaller segments aren’t useful or important, think again.

So, the bottom line here is that if you’re interested in the immediate gratification aspect, with no work, but also no ability to utilize DNA segments to find distant ancestors, Ancestry is the one.  Their strong suit is their tree matching and many people are perfectly happy to never go beyond that – replete with incorrect assumptions that this means the ancestral genetic relationship is “proven.”

I currently have about 5400 total matches at Ancestry.  Of those, the day I did this comparison, 152 people matched my DNA and we have a tree match as well, meaning a common ancestor in my tree and their tree has been identified.  Of course, that does not assure that particular ancestor is how our DNA matches, and we can’t confirm that without a chromosome browser.  Still having those matches and matching trees, along with Circles is a wonderful first step.  It’s “feel good” stuff and who doesn’t like feel good.

If you’re interested in the vendor that gives you the most DNA segments to work with along with the tools to do it and therefore the most opportunity, Family Tree DNA, hands down, is the one.  Less feel good but way more potential.

23andMe is someplace in the middle – not easy or intuitive with a difficult communication process resulting in very few people who actually share their matching DNA with you, no feel good stuff, but they have a great matching tool that shows you not only who you match, but who your matches match in common with you as well.

I wish we could combine the best parts of all 3 vendors.  I wrote in detail about the autosomal offerings of all three vendors here.  Today, the best alternative is to test with all three.

Regardless, everyone who tests with any of the 3 vendors (or all of the three vendors) should upload their results to GedMatch where additional tools are provided that aren’t available at any vendor.  Another benefit of GedMatch is that the people there tend to be more serious about genetic genealogy.  The down side is that percentagewise, few people actually do upload their files, so you do still need to test at all of the vendors to achieve maximum matching and benefit from their individual strengths.

Additional tools are also available at where you will find analysis tools that utilize the matches found at the vendors (via downloads) but provide analysis and display in different ways.

Gedmatch, which works with your raw data and provides comparisons to others, and which downloads your actual match information from the vendors are the great equalizers between vendors today, as much as possible given the vendor matching threshold limits in place internally.  No matter what, the third party tools can’t get more than the vendors give you.

What’s the bottom line?  Fish in all of the ponds, but understand the wide variance in the boundaries and the limitations of each pool.  There is more difference between vendors in ways that might not be initially apparent.

47 thoughts on “Autosomal Matchmaking Vendor Comparison

  1. I quite disagree with you I find these results quite close on the contrary. if one gave you 50cm and the other one 1000 ok it would be huge, but there are within the same range. and with gedmatch you can even choose the thresholds..
    for me matching allowed me to find my mum and the 2nd cousin was very accurate.

    • Close relative matching is going to be good at any of the vendors. That’s not really genealogical in nature. For working with more distant matches, we need every piece of information we can get.

      • it depends on what you seek. I still have to find my father so the closest one are the more important to me

        • Anyone seeking close relatives should test will all vendors. Your success doesn’t depend on small segments, but on matching someone on a lot of DNA. All vendors will be able to handle that.

      • I have to agree with both of you. For those seeking deep ancestry connections, the more information from FTDNA is a great help. For those looking more closer, I find the weeding out that Ancestry does very helpful. I agree 23andMe needs some help pulling all their information, which is why that is the next area of focus for DNAGedcom.

    • Roberta, forgive me for my ignorance, but if you have imported 23&Me data to FTDNA, it will only read what that data has allowed, correct? So for deeper ancestral connections, if they were deleted by 23&Me or Ancestry, would you need a separate spit test from FTDNA? I am looking for deep ancestral native ties. GEDmatch seems to pick something up, but inconclusive. My original testing with Ancestry and 23&Me was a few years ago,

      • Janette, I agree with Roberta. Your raw DNA data is basically the value of the 700,000 or so SNPs from both your parents. When you upload that data to FTDNA or GEDmatch, they treat it like a new test result and compare with all the other kits in their database (I believe FTDNA, at least, strips out any purely medical SNPs above the 700,000). The shared segments and Match lists depend on their (FTDNA or GEDmatch) algorithm and who is in their data base. For my own information, I submitted a new saliva test to FTDNA, 23andMe and AncestryDNA; I then uploaded all three to GEDmatch, and they each produced the same result (within the very small read error rate inherent in any such test looking at 700,000 markers). GEDmatch has a suite of Admixture programs – each one (like FTDNA, 23andMe and Ancestry), will provide a different admixture report – it’s fun to experiment with each one, but don’t bet the farm on any one of them.

  2. I agree with you except for their insistance on a 7cm cut-off minimum for the largest segment. I have 2 sibling third cousins, once removed and they are not on my cousins list at FTDNA because our largest matching segment is 6.9. We share 33cmTotal, but because we are 6.9 vs 7.0, they don’t count the match.
    They should have a way to adjust the cm’s like gedmatch does.
    Thanks for a GREAT article.

  3. Do you have an opinion as to which site might be more reliable on calculation of cousin relationship? I have five matches identified as third cousins and 116 matches identified as 4th cousins on ancestry. On FTDNA, I have one third cousin and 126 matches tagged as “2nd to 4th”.

    If I find matches who have tested on both sites who are identified as “4th cousins” on ancestry and as “2nd to 4th” on FTDNA, is it more likely that those matches on FTDNA are indeed “4th” cousins and not potential “3rd” cousins?

    And the same would go for 23andme versus ancestry. I tested there as well but haven’t yet checked to compare the cousin relationship status of those matches.

    • The problem is that predictions are made based on ranges and lengths of segments. Some predictions will be spot on, and some won’t be – at the same vendor. There is no more accurate way to predict, but by the very nature of averages, some will be in the middle and some will be outliers.

  4. Roberta – thanks for a great analysis. I concur wholeheartedly with your analysis and conclusions – test at all 3 companies and upload to GEDmatch. The name of this game is maximum IBD segments, and each of the 4 sites gives you segments and tools not available at the other 3 sites.

    One annoying bone to pick – Ancestry’s phasing… As I understand it, Ancestry uses “population” phasing; not true phasing using a two parent, one child trio. They somehow take a global summary of your DNA and select a proxy population sample that they feel most closely matches your DNA, and they “phase” your data with that. Which means to me that they discard Matches based on the proxy population. Say what? They are using something to weed out Matches, and it’s not your parents… How close to your parents could it possibly be? I would really like to see some opinions (Ancestry won’t tell us) as to how “population” phasing compares to parent phasing.

    And as long as I’m on an Ancestry rant, I’ll ask a similar question about their pile-up algorithm. What is the cM and/or SNP and/or total number criteria for that algoritm? Our Matches are doubling every year – so, too, are the segments in some Triangulated Groups. I’ve got some TGs with 50-100 segments – they are 8-20cM segments, triangulating with each other. Is Ancestry discarding these kinds of Matches. It would leave some bare spots on our Chromosomes with no Matches! Some ancestor had to provide the DNA for those areas….

    Anyway – I do like the Ancestry Circles, and am becoming a fan of genetic clusters. A process that helps, where triangulation cannot.

    Thanks again for a great post.

    • Jim, AncestryDNA has provided stats for the accuracy of their phasing method compared to known trios. I find it frustrating that I can’t provide a direct URL, but you can click on the help icon in the DNA Circles section. There’s a link within the DNA Circles White Paper to the Matching White Paper. Section 2.4 has a table showing a 1% error rate.

      The same paper describes the Timber algorithm in more detail. It’s not based on SNPs or cM, but on whether some segment generates a much larger set of matches compared to the rest of *your* genome.

      I do think the Timber algorithm needs to be refined. What I find more disturbing about AncestryDNA’s method is the large proportion of cases where a child has a match not found in either parent. Few people have reported their stats, and those may be biased toward the high end, but the numbers I’ve seen are upwards of 25%. These must be either false positives in the child or false negatives in the parent.

      • Ann, Thanks – I’ve read and printed and read again the Ancestry White Paper. I’m not sure what to say, except that my experience doesn’t match their claims. Maybe I just haven’t directly compiled enough Ancestry data at GEDmatch and compared it back to my Ancestry Matches – it’s hard to find those links. I get many new Ancestry Matches at GEDmatch – many of the Ancestry DNA customers are uploading their data there – and there are many good segments which triangulate and help me. But in most cases I cannot find the same Match at AncestryDNA! It seems that many of the the good Matches at GEDmatch (who have tested at Ancestry), do not show up as an AncestryDNA Match. So it’s hard for me to come to concrete conclusions. I’m not sure I follow all of their words about Timber and populations. I just don’t see how they can come anywhere close to phasing my results as close as I could with both my parent’s DNA. With my Colonial Virginia ancestry, it just seems like it would be hard to tease out the true IBD Matches that were mine…. And I’m hampered by my feelings about the Ancestry hype. I remember the 10s of thousands of Matches I had before; I’ve seen their claims for Circles; I’ve read their claims of finding my ancestry – and every day I open my Ancestry account to the pictures of 2 folks who cannot be my ancestors…

  5. Great article Roberta – Thanks! One question I would like answered is the quality of the actual test. I tested at Ancestry and transferred the results to FTDNA. Is there any significant difference in the actual DNA test at the two companies? In other words if I tested at FTDNA would I likely see different matches?

    • I know that FTDNA has quality standards that have to be met for their own test results to be uploaded to a participants personal page. So for Ancestry results, they have to meet the same standards for uploading. The reason that the V4 chip at 23andMe isn’t accepted for transfer is because they test enough fewer locations that it doesn’t pass QC at FTDNA, so can’t be uploaded to the participants page. The V3 chip tested more locations and passes QC. I don’t know of anyone who did a comparison between an Ancestry transfer kit and a FTDNA original kit as to matches and differences, but would welcome input from anyone who has information on that topic.

      • I accidentally gave my brother in law a Family Finder test after he had already run a Transfer. (I meant to give him a kit with YDNA, but grabbed the wrong kit). The results were similiar, but I’ll run his new kit through DNAGedcom to and then do a one to one comparison. Interesting to see if there is any difference.

  6. I am glad you came up with FTDNA. But my cousins are on a big push to test with Ancestry, so I did too. I uploaded my raw data to FTDNA, but should have put that fee toward independent testing there. Oh well, live and learn. Thanks for this article!

  7. David, I’ve tested (original saliva sample) at all 3 companies, and have uploaded them all to GEDmatch. I also have Matches who have tested at all 3 places in my spreadsheet. In virually every case, the results are ever so slightly different, but they sort in my 8,000 line spreadsheet to within two rows of each other. In other words there is no appreciable difference. As has been pointed out before there is perhaps a few read errors in every test, and very, very few of these affect the results.

  8. My eyes lit up when I read that you were able to use a “new private tool currently in beta test” to compare your data. What would be the possibility that someone in the general population, not a genetic genealogy blogger, be allowed to participate in the beta testing? Like yourself and many others, I feel the lack of quality tools at to be it’s biggest shortcoming.

      • My experience with the (apparent) missing segments from the total cM reported by the “new private tool currently in beta test” is very similar to Roberta’s. In my case, I think it may often be due to the way Timber deals with endogamy. For example, I have several cousins who descend from a set of my 4th great grandparents 2-4 different ways and *all* the shared segments are triangulated with several other cousins. Ancestry (i.e., Timber?) appears to routinely eliminate some of these segments.

  9. I am so thankful that I did the research before deciding which vendor to use. I chose FTDNA and I supplement my work with gedmatch. I’m still learning but I am learning so much more than if I had gone with one of the other vendors. Your blog is also a valuable part of my learning process. Thank you!

  10. Roberta, I’ve tested myself with all 3 vendors and have (unbelievably) never asked this question! I have only uploaded my FTDNA results to GEDmatch because I expect them to be the best. Other than doing the kinds of comparisons that you did for this article, would there be any reason that I might want to upload 23andMe and Ancestry results, too?

  11. I luv the small segs… M.M. is my cuz; Arne is an X match w/ us. pat davis in OH

    Comparing Kit F244618 (*DavisDNA_PD) and F422411 (Hans Joachim Schultz)

    [ArneSchwarck’s maternal uncle]

    Minimum threshold size to be included in total = 300 SNPs

    Mismatch-bunching Limit = 150 SNPs

    Minimum segment cM to be included in total = 3.0 cM

    Chr Start Location End Location Centimorgans (cM) SNPs

    1 25,274,024 29,047,639 3.1 710

    1 117,439,793 144,278,803 3.1 777

    1 235,757,907 238,038,542 5.3 689 lap M.M.

    1 240,360,541 241,777,030 3.1 351

    1 243,919,011 245,606,936 3.4 443 18.1cM total, chromo 1

    2 192,738,769 197,852,247 3.3 751

    2 218,594,044 220,500,564 3.2 496

    3 24,491,068 26,852,206 3.2 644

    3 141,742,966 144,278,127 3.3 524 lap M.M.

    4 16,382,421 18,450,525 3.2 430

    4 82,814,281 84,817,306 3.1 415

    5 15,048,390 17,820,309 4.7 595

    5 87,867,490 91,820,476 3.3 623

    6 138,198,118 139,687,364 3.1 393

    8 137,622,314 139,160,156 3.2 396

    9 1,751,505 2,583,108 3.1 427

    10 2,103,955 3,175,393 3.4 533

    10 44,114,283 50,088,479 3.2 868

    10 130,837,206 131,833,413 3.7 305 10.3cM total, chromo 10

    12 6,173,418 7,673,892 3.6 414

    15 98,564,431 99,466,934 3.0 349

    17 72,587,275 73,773,839 3.8 400

    18 7,108,955 8,290,337 5.5 366

    18 8,968,365 9,995,486 3.3 365 8.8cM total, chromo 18

    19 9,011,838 10,599,639 3.4 356 lap M.M.

    20 6,767,428 7,999,353 3.2 360 lap M.M.

    Largest segment = 5.5 cM

    Total of segments > 3 cM = 90.6 cM

  12. Thanks for this eloquent analysis. It validates my problems with Ancestry v2 regarding the high false negative rate impeding distant relative genetic genealogy. I have been negatively affected by Timber removing matches on a segment that is just under 30 cM. I am glad I saved my v1 match information with AncestryDNA Helper but the fact that AncestryDNA is calling all of these matches “false” impedes finding collaborators and is false on its face.

    I am heartened that thtere is a new tool in beta test. As for uploading all three tests to GEDmatch, my experience is that the differences are few but there is still the possibility of missing something important if all three are not uploaded. Mostly, I think it depends on how many matches you have to work with and how far back in time you need to go in your research. Some have suggested that we are only “supposed” to upload one test, but I do not see this stated anyplace on the website.

    An important point is that ethnicity DOES matter regarding where one does autosomal testing. I cannot currently suggest that African Americans (AAs) test at FTDNA as the first or only place of autosomal testing unless they are at least 30-40% European. In general, AAs will not get enough matches to make the investment worthwhile. In cases where AAs could get 1,000 matches at 23andMe or AncestryDNA, AAs are often getting less than 50 total matches at FTDNA. This is not acceptable! What are they doing to the AA data? Some sort of phasing?

    I am AA, and it feels like double jeapordy with AncestryDNA removing large Europen (EU) segments with Timber (like an AA is likely to come from the “same population” an endogamous EU segmant is associated with) and FTDNA just plain old refusing to acknowledge my EU matches at all! Thank goodness for GEDmatch!

  13. Roberta, I must vigorously disagree with your statement “Family Tree DNA does us the HUGE favor of providing all the actual matching DNA segments over 500 SNPs..” In my view, it is a HUGE disservice to include 1 and 3 cM segments when a very high proportion of them are pseudo-segments, which would disappear if the data were phased. I have illustrated this with a phased kit at FTDNA

    Dianna Harbin, I believe the above blog post has some bearing on the impediments the FTDNA algorithm creates for AA. It is harder for AA to reach the 20 cM threshold, while Europeans can often (but not always!) cobble together enough small pseudo-segments to get there. My JoGG article “Identify Crisis” shows how pseudo-segments can arise.

  14. Roberta, I also thank you for yet another insightful and thoroughly written article.
    My question is this – just curious, but do you recall the range each company (including Gedmatch) estimated your relationship to be with Harold?

    Thank You.

  15. Thank you once again for a great article. I never lowed the cM threshold, thinking it was to small to use for any benefit. Hmmmmm.

  16. Regarding 23andMe, you say: ” no feel good stuff, but they have a great matching tool that shows you not only who you match, but who your matches match in common with you as well.” Can you point me to the “tool” they have that shows us who matches our matches? Are you talking about the “COUNTRIES OF ANCESTRY” csv download?

    • I use both CoA and FI:A. I sort the Match’s CoA by Chr and Start, then find myself and highlight the overlapping segments. The ones I have in my spreadsheet which also overlap, Triangulate. At FI:A, I enter a base Match, then my other Matches which overlap. The ones which overlap the base Match, Triangulate. In general these are different Matches, so it pays to use both programs.

  17. Roberta,
    Great article! I have documented 6 good matches so far who tested on Ancestry and are good matches via GEDmatch, however, they don’t show at all on Ancestry. One helped break through a brick wall for both of us (one large segment at 10+ cMs). Another example is an adoptee who matches 3 full sibling tests that I manage – all with matches of more than 20+ cMs in a single block. They show on GEDMatch but not at all on Ancestry for any of them. That is way too large to be bypassed.

  18. Thanks for a great article Roberta. The smaller segments triangulating is something I have been seeing a while. I first started noticing the smaller segments because the accounts were either administered by the same email account or the the matches had the same last name on Gedmatch when I lower the threshold. Since Gedmatch started charging to triangulate, I do a roundabout triangulation with the other tool, which produces the same results but just takes longer.

    I too was seeing matches on Gedmatch from multiple groups of family members that were not on Ancestry who tested with that company. I do realize Gedmatch uses a smaller threshold and allows us to adjust, so that accounts for some of the discrepancy but not all.

    The problem with the smaller segments is that many people, including genealogists, think those guidelines are set in stone. If people feel the smaller segments are not valid, they are even less willing to communicate and share trees or any other genealogical info.

    Ancestry seems to believe all the “feel good” hype from their own marketing team that everyone who tests there is more than willing and happy to share info regarding family trees. Of course, anyone doing research knows that is not the case. From locked trees to unanswered notes, it is extremely frustrating at times. I have 100 4th cousins there, of which about 2 or 3 I know how we are related, even though the matches may not because they never responded to my notes. Lol. Oh well…..

    • Family Inheritance: Advanced

      It’s not the same as FTDNA’s ICW tool, which gives you a list of people who appear on the match list for you and one other person — but you can only see the segment information for yourself compared to people on the list. FI:A lets you compare anybody with anybody on your sharing list, but you need to enter the names (one on the left side, up to five on the right).

    • Cindy;
      The FI:A tool lets you confirm triangulation among you and 2 of your Matches. You have to enter the Matches and see if they match each other. It does not produce an ICW list.
      The CoA tool lets you download a spreadsheet for each of your Matches who have taken the survey and/or who have shared with you. Each of their spreadsheets lists their Matches who have taken the survey. This does not include all of your Matches who have shared genomes with you, only the ones who have independently taken the CoA survey – some have, some have not. It also includes other Matches who have taken the survey, but who have not Shared Genomes with you – so you get some extra Matches (and segments) through the CoA lists. Anyway, if you sort a Match’s spreadsheet by Chromosome and StartLocation; and then search for your name; you can see all of your Match’s Matches who overlap with you. The Matches who are also in your own spreadsheet at this location are ICW you, and are Triangulated. So each Match’s spreadsheet usually has some Matches who are ICW you, and by sorting their spreadsheet, you can identify which ones are Triangulated.

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