Endogamy and DNA

I really enjoyed the presentation Paul Woodbury of Legacy Tree Genealogists did about Endogamy last year at the SCGS Jamboree so I am delighted to present this guest post from him on that topic.

Personally I struggle with the endogamy in my mother’s family tree. My jewish grandad was an only child so there are not that many close cousins on his side. However due to endogamy my maternal aunts have hundreds of 2nd-3rd/4th cousin matches. No wonder I spend more time working with the easier Norwegian DNA from my Dad!

Endogamy and DNA By Paul Woodbury

Autosomal DNA testing is a valuable resource for genealogists seeking to overcome recent brick walls in their family history, particularly in instances where traditional historical research is limited or unavailing. At Legacy Tree Genealogists, we frequently use autosomal DNA test results to answer questions regarding adoption, unknown paternity, or ancestors who are difficult to trace. However, there are some factors that can complicate the use of autosomal DNA in tracing ancestors. One of those factors, which is what we will be discussing in the article, is Endogamy.

Endogamy is the custom of marrying only within the limits of a local community, clan, or tribe over the course of many generations. The reasons for this genetic isolation could be cultural or religious (as with Ashkenazi Jews and Low-German Mennonites) or geographic (as with island and tribal populations). Members of endogamous populations may descend from a limited pool of “founder” ancestors who represented the initial genetic makeup of their population. After many generations and hundreds of years of isolation from outside pedigrees, genetic profiles of population members can easily be distinguished from the DNA of outside populations. However, this can also cause pedigree collapse.

Pedigree collapse occurs when two closely related individuals produce offspring. As a result, the number of unique individuals occupying locations in a pedigree decreases or “collapses”. For example, while most people have eight unique great-grandparents, a child of two first cousins will only have six unique great-grandparents. They will also have inherited a larger portion of their DNA from the ancestors held in common between their parents. This makes it more difficult to determine exact relationships between genetic matches.

Here we explore three keys for dealing with endogamy in autosomal DNA test results: 1) Exploring the exact amounts of shared DNA between relatives; 2) Testing multiple relatives; and 3) Using direct line tests to narrow results.

1) Exploring Exact Amounts of DNA

Runs of Homozygosity

In order to accurately evaluate DNA test results in endogamous populations, consider exactly how much DNA two individuals share in common. Most genetic matches will only share DNA segments on one copy of their chromosomes – either maternal or paternal. However, if both of an individual’s parents are from the same endogamous population, or are known close relatives to each other, then they may have a “Run of Homozygosity” (a region of their DNA where the maternal copy is identical to the paternal copy). In these cases, the subject is a genetic match to themselves. If another genetic cousin overlaps in this same region of DNA, then the amount of DNA that person shares in common with the test subject should be doubled for that particular segment since they match the maternal copy and the paternal copy.

None of the DNA testing companies report total amounts of shared DNA which take into account runs of homozygosity. However, these regions can be discovered through analysis at Gedmatch.com and through David Pike’s Utilities, and might be used to confirm and refine the total amounts of shared DNA between two individuals. However, the researcher must have access to test results for both the subject and the genetic match in order to perform these comparisons.

Applying Different Centimorgan Thresholds

In endogamous populations, much of the population shares extremely small segments of DNA from many distant ancestors. If these small segments of DNA are included as part of the total shared DNA between two individuals, it can skew the estimates for how closely they might actually be related. At
Family Tree DNA, all segments larger than 1 cM (centimorgan) are included as part of the total shared DNA. At Ancestry, all segments larger than 5 cMs are included; however, some larger segments may be excluded based on their matching algorithms. At 23andMe all segments larger than 5 cMs are included as part of the total. Depending on the nature of the endogamous population, it may be beneficial to recalculate the total amounts of shared DNA between matches through comparison at Gedmatch and through application of higher centimorgan thresholds. For example an individual may share 120 centimorgans at Family Tree DNA, but when segments smaller than 7 cMs are excluded, this total may drop to 60 or 70 and may be more representative of the nature of their closest relationship. The appropriate threshold to apply in any given case will depend on the amount of endogamy within a population and whether the test subject is a full member of that population or has recent admixture from outside populations. Consider calculating several totals using different thresholds to give a better indication and overview of the shared DNA.

2) Testing Multiple Relatives

Since different descendants of an ancestral couple inherit different segments of DNA, it is always a good idea to invite additional relatives to test when exploring a brick wall problem. Other relatives will have different segments and will therefore have different matches as well. When dealing with endogamous populations it is particularly important to test as many known relatives as possible. When dealing with a case of unknown parentage or adoption, collaborate with genetic cousins and work with them to test more of their known relatives, focusing first on the older generations of their living family. Even if you know that specific relatives may be related through multiple family lines, test them anyway; their test results will greatly assist in filtering and organizing your matches.

Create Complete Trees

In endogamous populations it is quite likely that close relatives will be related through multiple family lines. Therefore, it is essential to have trees that are as complete and far back as possible for each relative tested. Since shared segments of DNA may (and often do) come from more distant relatives in endogamous populations, consider extending family trees 7 generations or more. This will not only permit researchers to identify the multiple ancestors shared in common with the relative, but will also aid in the exploration of the multiple relationships that the relative has with other relatives and genetic cousins.

In some cases, it may not be possible to build extensive family trees for relatives. Record loss or limited availability may prevent the construction of detailed multi-generation family trees. In these cases, consider documenting and focusing on the ancestral origins rather than ancestral couples. For example, in Ashkenazi Jewish research, try to identify the ancestral villages in Eastern Europe for genetic matches. This may help to tie brick wall ancestors to specific localities and regions.

Obtain Shared Segment Data for All Relatives

Though each of the DNA testing companies offers information regarding relatives that a subject holds “in common with” genetic cousins (also known as ICW), in order to be useful in the investigations of endogamy, researchers must also have access to the actual test results of other tested relatives. It is not enough to know that a genetic cousin matches a known relative. In an endogamous population we can expect that most members of the population match many other members of the population. We also need to know how much DNA they share with that relative. Some people may not be willing to share their specific results, but if you explain what you are trying to do and offer to share your findings, many people will be happy to help.

Exploring Averages and Assigning Segments

Testing multiple relatives and obtaining access to the test results for multiple relatives allows researchers to evaluate relationships between a match and a larger group of known relatives. By calculating the amounts of DNA shared between a genetic cousin and multiple relatives, it is possible to more accurately estimate the nature of relationships. Knowing that a subject shares 200 cMs with a genetic cousin, and that three first cousins of the subject share 69, 139, and 150 cMs (average of 139 cMs) with the same genetic cousin might lead us to estimate that the match is related at the level of second cousins once removed (or some equivalent relationship rather than at the level of full second cousins). By averaging between multiple relatives, researchers can identify the most likely level of relationship.

Access to the test results of relatives also permits the investigation of unique shared segments of DNA which could be representative of how much DNA a match might have shared with the common ancestor of multiple known relatives. Performing this type of research with multiple close relatives can also aid in chromosome mapping, which in turn can identify the segments of DNA that were inherited from a specific brick wall ancestor. Assigning segments of DNA to particular ancestral lines and sifting through the relationships between multiple family members enables researchers to identify and focus on the most pertinent matches to a particular research question.

3) Using Direct Line Tests to Narrow Results

Autosomal DNA analysis in endogamous populations can get messy quickly, so testing additional relatives with direct line tests (Y-DNA and mtDNA) and encouraging genetic cousins to do the same can help to narrow the possible relationships and can give increased structure to the investigation. Wherever possible, attempt to perform DNA testing of specific relatives in order to determine the Y-DNA signatures of each great-grandfather and the mtDNA signatures of each great-grandparent. Encourage genetic cousins to do the same for their own family. Direct line tests can serve as anchors and guides for interpretation of autosomal DNA test results and can identify family groups within a single pedigree that are likely related to each other.

Paul Woodbury is a Senior Genealogist with Legacy Tree Genealogists, a genealogy research firm with extensive expertise in genetic genealogy and DNA analysis. To learn more about Legacy Tree services and its research team, visit the Legacy Tree website at https://www.legacytree.com

44 thoughts on “Endogamy and DNA

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  1. In cases where only one grandparent is Jewish, can that be used to do a rough phase of DNA results? Can we expect that all of the AJ segments will appear only on one copy of every pair of chromosomes?

  2. Can I get your views on the following instance I am working to resolve for my family?

    Four full siblings tested on Ancestry. All four siblings have between them from 13-28 percent AJ. We strongly suspect it is the four sibling’s unknown grandfather who was AJ. Let’s call them Group A.

    Four other people who are known second cousins to each other (who are not siblings) also tested – three on Ancestry and one on MyHeritage. Let’s call them Group B.

    Luckily, there is a well-respected family tree website created by two academic genealogists which allows me to confirm the relationships of Group B members to each other, ie, they are all second cousins to each other. There has also been other family research and family reunions that confirm the relationship.

    Following my research, I propose Group A and Group B are also second cousins to each other.

    The range of shared DNA from Group A members to Group B members is quite large – from very low 95 in MyHeritage, so very high 426 in Gedmatch!

    I have managed to copy all of Group A profiles and two of Group B profiles to Gedmatch. I can now see that the two people in Group B (R.T and H.G) are also low in shared cMs to each other:

    Largest segment = 27.4 cM
    Total of segments > 7 cM = 95.6 cM
    6 matching segments
    Estimated number of generations to MRCA = 3.6

    Does my hypothesis still stand given that there seems to be a precedence in the family for a result like this?

    I would like to add, just to complicate matters further, that there is a 4C1R that is also showing up just as strongly as the above proposed 2Cs. But again I can verify that they are 4C1R.

    Thanks for your insights!

    • This is too long for a blog post comment so I will send you an email.
      However I doubt they are full 2nd cousins. Look like half 2nds to me

      In my experience true 2nd cousins will share many large segments (> 10) including at least one > 30cM, particularly in endogamous populations.

  3. I am trying to solve a mystery of how I am related to a gentleman with only one known ancestor from the same area as my own ancestors, namely Pomerania (or somewhere else in Germany). He’s usually my number one match on most sites (e.g. GedMatch, My Heritage) and yet I cannot connect his Jewish G grandfather to anyone on my own family tree (ALL German). We both do have relatives who lived in the Stettin area circa 1871. And there was a rumour (according to my mother) that we had a Jewish ancestor. (Both my maternal grandparents looked rather “dark” for people with significant Frisian ancestry, and they both had ancestors with surnames that could be either Jewish or German. This is very common it seems.) We are also about 10 years apart in age; so we may be off by one generation, I’m guessing. His “Stettin” G grandfather was almost a teenager, for example, when my “Stettin” G grandfather was born.

    Here’s what I see when I compare my closest cousin match to my DNA kit at GEDmatch:

    Total CM: 71.5 Largest segment: 38.1 Estimated Generation: 3.8

    Incidentally, further down on most lists, I also see people with Jewish surnames and/or who show large amounts of “Ashkenazi” as their ethnicity. Many of these matches ALL share the same DNA with me on an overlapping bit of Chromosome 9. Yet my number one match does not share this same DNA.

    So, finally the questions:

    1) For any of these matches, is there anything that could be inflating our shared DNA results. Otherwise, it seems that someone changed or concealed records or there was some exchange of DNA outside of marriage.

    2) Is there something about endogamy among Ashkenazi Jews that is bringing a very distant ancestor closer? I must say the DNA hints at a Jewish ancestor. It’s very confusing to a novice but I don’t see how I could be related to all these people who have much, much more Jewish ancestry, especially with that one overlapping bit. Wouldn’t it be quite a stretch to guess that we all have one common European ancestor, who got one common Ashkenazi pregnant?

    I’ve tried to exclude matches under 15 CM on the largest strand/bit and I still have some of these Ashkenazi matches (some still with another bit of other DNA).

    Yet I do NOT have Ashkenazi as part of my identified ethnicity at various sites (Ancestry/FTDNA/MyHeritage/DNALand), except once, under >1%. I do get things like 3% West Asian, some combo of south Italian and west Med (about 5%) or just variations of Northern Europe stuff (English???, Scandinavian???, Eastern European).

    Any thoughts? Thanks for your time. It’s been my summer project but I’m about to give up. My cousin match is not. He’s been doing this genealogy stuff for years now. We’ve tried contacting the one other shared match we have in common. She only knows that she’s English and Scottish and doesn’t want to dig. She’s his second cousin apparently. Too bad, eh.

  4. Heidi
    There are very few Germans who have tested so that may explain why such a distant match, at best a 3rd cousin, perhaps a 4th, is your top match.
    Most likely a 2nd/3rd/4th grandparent of yours from Stettin married into the Jewish community. Or as you suggest, midattributed fatherhood … if you do not see any Jewish in your DNA or your cousin’s (try the eurogenes Jtest calculator at GEDmatch) that is the most likely explanation.
    The frequent intermarriage among family members in the jewish community can also make a distant match seem closer when DNA is coming down from the same ancestor more than once.
    Finally, it is unlikely that you will solve this puzzle unless you both get alot of cousins to test and you can find records back to the 1600s for both of your families in Pomerania.
    Interestingly my 100% father also has a pile up area on chromosome 9 which matches many russians and poles and some ashkenazim!
    Enjoy this journey!

  5. Thanks so much!
    Yes, my Ancestry.com cousin has some “European Jewish” as does our shared match and a shared match of that match… whom I already knew about before DNA genealogy, etc. I think someone assimilated in my family. There are just too many hints. I’ll keep hunting and delicatedly ask the only “German” cousin in this group. (I also have “Ashkenazi” on the Jtest but thought it was invalid.)

    I’ve really enjoyed reading through your many interesting blog entries.

  6. Hi!

    Trying to figure out the relationship with a DNA match on 23&Me.

    16.2% shared DNA
    Half identical
    1207 cM
    26 segments

    Any thoughts?

    • You really can’t tell for sure from those numbers although it looks like a 12.5% relationship with perhapsd more relatedness (this is an endogamy post, is that also an issue?)
      The calculator at https://dnapainter.com/tools/sharedcmv4 gives various options: most likely a half aunt/uncle/niece/nephew but can also be a high 1st cousin. Ages of the matches and the amount shared by other matching relatives can help sort this out.

      • Kitty,

        This is a match between my father, who was born in 1948 and a woman who was born in 1975. They matched on 23&Me. She does not know who her biological father is. My paternal half-brother also matched with her on Ancestry DNA with 596 cM and 20 shared segments. I just got a kit and need to send it off so I can compare my own DNA to hers.

        The shared segments between this woman and my father are VERY large… Here are some of the larger shared segments:
        #1 – 104.60cM (& 35cM)
        #2 – 226.20cM
        #4 – 95.35cM & 62.86cM
        #11 – 73.12cM (& 8.94cM)
        #12 – 56.64cM
        #13 – 72.55cM (& 13.74cM)
        #16 – 84.81cM
        #20 – 55.22cM

        There are other, smaller shared segments, but those are the larger ones.

        Not sure if endogamy is an issue or not. There seem to be some odd stories regarding my grandfather and his siblings’ youth. My paternal grandfather, as well as his siblings, did not have much of a relationship with their father as adults (my dad did not know his grandfather lived near him until after he passed away). My dad did not know he even had as many 1st cousins or aunts and uncles as he does.

        Due to the size of the segments shared though and the total amount of cM shared I would imagine that this woman’s father would be a brother or half brother to my father. We are unaware of a brother as of now though. My father does have a sister who is 9 years his senior and their parents did separate for a while at some point between his and her births. My grandfather would have been too old to be this woman’s father so I feel like there must be a missing brother.

        I am working on getting other cousins with known genealogical relationships to upload their raw DNA data to GEDMatch so I can view a more complete comparison since you can’t really see much on Ancestry.

        Your blog has been SO informative and helpful and I am learning so much!

        Here are the results from the DNA Painter:

        Relationship probabilities (based on stats from The DNA Geek)

        82.36% Great-Grandparent Great-Aunt / Uncle Half Aunt / Uncle 1C Half Niece / Nephew Great-Niece / Nephew Great-Grandchild

        17.64% Half Sibling † Aunt / Uncle † Niece / Nephew † Grandparent Grandchild

        † this relationship has a positive probability for 1207cM in thednageek’s table of probabilities, but falls outside the bounds of the recorded cM range (99th percentile)

        Any guidance or thoughts?

  7. Men have fathered children into their 90s … The numbers suggest your grandad fathered her dad or less likely fathered her .. So she is most likely your and your half brother’s half first cousin and your Dad’s half niece
    Endogamy is not a factor in close family matches.
    You are doing the right things by getting more relatives to test like yourself. Are there other cousins who would test? Will your dad’s sister test? More important to test her than yourself or anyone else; If she shares X with the match that can be a big clue, the entire X would suggest half sisters.
    Keep up the good work!

  8. I recently came across a DNA match with me who has a largest shared segment of just over 5cM, but has about 15 other shared segments in the range of 3 to 5cM. Would this be indicative of a common ancestor from an endogamous population?

    • No, small segments like those are not meaningful for relative matching and we do not usually even look at them.
      They usually just mean that the kits are from the same population group, say Spanish, Irish, Greek, Swedish, or whatever … but are not necessarily related in recent times.
      Typical of an endogamous population are large matches with a few 7-10 cM segments that look like a 4th cousin but in fact are not related in recent times perhaps 8th cousins many times or …

  9. I am so grateful for this article. Although I am 2 generations removed from my endogamous ancestors it showed up when I got my Aunt’s DNA results and we were a 30% match. It’s going to make it more difficult to find MRCAs in my cousin matches. Thanks for the references from other contributors in dealing with this. BTW my endogamous group is Acadian.

  10. Thank you so much for this post! It was a shock to learn that my brother was actually a half brother, and an equally large shock to learn that my half brother’s father was likely born in Colombia. I’ve learned that cousin marriage is very common in Antioquia, and after several months I finally figured out that a huge majority of my brother’s matches all descend at least once (but in many cases through multiple lines) to one man born in the mid 1700’s that had 5 wives and 29 children, and even founded a town in Antioquia. I thought all hope was lost – he had so many matches in the 3rd cousin range, and even if I was able to find MRCA’s for small clusters, they would be related to other clusters through that one ancestor back in the 1700s.

    I started researching more about strategies to deal with this particular issue, and stumbled upon a post on facebook that mentioned focusing on matches with not only high CM matches, but a shared largest segment over 20. After uploading my brother’s DNA to MyHeritage and FTDNA, the picture is getting clearer. I’ve found matches that meet the higher CM threshold (over 90cm) an also have a higher shared largest segment (30s & 40s). I think many of these matches, based on age, or more likely to be a 1st cousin twice removed, or a 2nd cousin once removed (my brother is in his 30s, and these matches are in their 60s-80s). On another comment you mentioned more than 10 segments shared and at least one over 30 for a true 2nd cousin match. Would those thresholds be the same for 2nd cousin once removed, or first cousin twice removed? Is there a table somewhere I can reference?

    Thank you again for this wonderful post!

  11. Hello,
    May I say I always come back to your site Kitty when I need to understand DNA. But this small detail is bugging me.
    May I ask….if a Great Grandfather with endogamy running through his family all the way back, is married with children during 1760-ish and he then forms a relationship with another woman and has an illegitimate child with her, will the descendants of that illegitimate child find it difficult matching with DNA to any descendants living now of his legitimate family?
    The illegitimate child would have been half sibling to the legitimate children of the marriage.
    Obviously, names of the legitimate children and the other child would be entirely different due to the secrecy then.

    I also notice that the couple of matches that are there go way way back….matched with grandparents in 1714.
    Also, one member kindly provided their kit number which was put into Gedmatch and lowered the threshold to 5……there was a match at 5.5 and this worked out exactly by related cousin generations.
    I read somewhere never to dismiss anything around 5 cMs.

    I’m so looking forward to your advice.
    Kind Regards.

    • Endogamy would result in more matches, not fewer and smaller ones.

      2nd cousins will always match and half 2nd cousins just about always. See
      But sounds like he is further back? How many generation

      And no, segments less than 7cM are not counted for matching

      Can you compare DNA to other descendants?

  12. Gedmatch give the 5.5 match at 7.7 generations. Which I thought would be around 1800s-ish, (I may be wrong though) which is about accurate to the possible/my possible Great Grandfather’s generation.
    My matching person at 5.5 informed me that he is a 2nd cousin 4 times removed to this possible Great Grandfather. I also measured my match to his Mother who is on Gedmatch and she was matched to me 5.4cMs and 7.7 generations. His Nan is also on there and she was 5.1cMs and the same 7.7 generations.
    No other people match with me in his list of matches. Well, I only checked 7 others and none of them matched with me at any threshold. There’s literally hundreds on that site.

    I don’t think there’s many people in this ancestors family that have been DNA tested, and to be honest they wouldn’t need to as there’s already a One Name Study Family Tree going back to 1400s that someone is working on. So I don’t think there would be much interest shown in DNA for research.
    It appeared (according to MyHeritage) when I spoke to them, that there’s very few with the particular name in the data base. She thought it strange that there were no family circles either.

    There is DNA matched with me on Ancestry.com to other people in that specific family tree I mentioned above….Great Great Grandparents. My matches are around 10-12cMs. And these people, all 5 of them match with Great Great Grandparents in this Tree.
    Then there’s other distant matches…4 people who are linked with that Tree.

    I understand that anything below 7cMs isn’t taken as a match and they ignore that estimate. But could it be at all possible that there may be a relationship based on the other factors I’ve mentioned above?

    Thank you and kind regards.

  13. May I add, the above third paragraph regarding the several matches on Ancestry.com…..after double checking the cMs are between 6 and 7…..not 10-12 cMs. My apologies.

    Thank you.

  14. I have been working on an unknown close match (2061 cM) to my mother through My Heritage for almost 2 years.

    Her entire tree is New England, mostly concentrated in one state, with names overlapping between her parents. Can this be a factor in the high cM? In trying to figure out this match, most of the possible timelines do not make any sense.

    Thank you!

  15. I’m trying to learn my lineage with the help of a volunteer experienced in searches. We have sorted out my matches into a paternal and maternal side. The paternal side seems to have endogamy based on a Leed’s chart, color Cluster, inspecting trees, and large # of matches.

    You wrote “Endogamy is not a factor in close family matches.” My question is, at what point is it a factor? We have a potential b-dad candidate chosen because he would be the link between cousins from 2 separate tree branches (?). Those cousins cM are 564, 548, 529, and 449, which could all be 1C1Rs. However, if the b-dad candidate is correct, then the tree placement of the cousins is a generation removed, to 2C. Would endogamy account for that?

    If it’s okay, I have another question. I sorted my top 250 matches into the 2 sides by examining each one’s shared matches. They all divided out neatly except 8 that had ICW on both sides, within their first 6 or so shared matches. The cMs of the eight are 106, 99, 97, 94, 78, 66, 53, 50. Is there any significance to having 8 in common like that, worth investigating, or just an expected statistic? Thank you.

    • Thanks, the charts and your answer helped. I thought that endogamy would have a much larger effect.

      I am an absolute neophyte, just since my test matches 20 days ago, and have already benefited from your articles a number of times. Jim

  16. Hello. I am trying to find my birth father. I did the ancestry, ftdna, myheritage, 23andme, and gedmatch dna kits. Sorting through paternal and maternal I noticed my matches are intertwined with each other from both sides. I used the aypr tool at gedmatch and it said my parents are likely related from the past several generations. Endogamy. How can I know which dna match is strictly from paternal side and which is from maternal side without endogamy interfering?

  17. Hi Kitty

    Any thoughts on 684 shared cM on Ancestry, 42 segments, one person half Italian (all matches have recent immigrant parents/g-parents etc) from one village in Italy. The match is 100% Italian, one grandparent emigrated from same village, the other grandparent from a village about 80 km away.

    Match won’t upload elsewhere.

    I am having trouble believing the “horse not zebra” of 1C.


    • Always use DNApainter to check the possibilities
      note half 1C and half niece/nephew are in the mix
      could the match have a half sibling who could be one of the parents? Or a parent with a half sibling?

      Ancestry is pretty good at removing endogamous segments but you can always retry the total minus 10% when endogamy is at work for other possibilites on close matches

      do both people have good trees or is one an adoptee? Either way look for a recent MPE (misplaced parent event) based on other matches …

  18. Thanks. DNAPainter isn’t good for endogamy (nor is WATO). Match has a horrible tree and isn’t interested in correcting it, or uploading elsewhere. Person 1 is an adoptee. Any MPE will be someone in that community who traces back to the same village because that is where EVERY match for Person 1 leads on this side. Subtracting 10% is a good idea. Thanks.

  19. Hi I have been searching for several years for the parents of an ancestor from an endogamous population (Acadians). He came to Australia in 1855 so there was no further mixing which I am assuming may provide an advantage. I have two potential parents for him now, found using traditional methods not DNA. Can you advise the best strategy to try and confirm or exclude these two? I would like to gain DNA evidence for this theory and have tried many methods quite extensively, GEDMATCH tools, My Heritage and FTDNA clustering etc and looking at segments but nothing clear has appeared so far due to the many matches and repeating names. Y-DNA has helped but still not for the exact line as only a few have tested to Y-111. Have tested several family members on FTDNA but probably can’t access more cousins etc easily for more testing as they are interstate etc. I have read your blog above and try to do each of these steps but wondered whether this is a futile case as some traditional non-DNA researchers have suggested it might be impossible and discouraged further examination of it. Thanks for any further tips. Liz

  20. Dear Kitty, have been searching for several years for the parents of an ancestor from an endogamous population (Acadians). He came to Australia in 1855 so there was no further mixing which I am assuming may provide an advantage. I have two potential parents for him now, found using traditional methods not DNA. Can you advise the best strategy to try and confirm or exclude these two? I would like to gain DNA evidence for this theory and have tried many methods quite extensively, GEDMATCH tools, My Heritage and FTDNA clustering etc and looking at segments but nothing clear has appeared so far due to the many matches and repeating names. Y-DNA has helped but still not for the exact line as only a few have tested to Y-111. Have tested several family members on FTDNA but probably can’t access more cousins etc easily for more testing as they are interstate etc. I have read your blog above and try to do each of these steps but wondered whether this is a futile case as some traditional non-DNA researchers have suggested it might be impossible and discouraged further examination of it. Thanks for any further tips. Liz

  21. Hi Kitty

    Thanks for the article about Endogamy. I am working with a foundling born 1972 in Haiti and am wondering if there is any way to discover whether endogamy is affecting her DNA results.

    She has three clusters, one is large and very complex. Male born 1889 has fathered at least 29 children with 8 partners – my founding has many DNA matches to descendants. Of particular note are matches to nine of his grandchildren (from four different partners), those matches are from: partner 1 – 182CM, 243CM, 259CM, 194CM;
    partner 2 – 207CM, 120CM, 186CM;
    partner 3 – 196CM;
    partner 4 – 247CM, 217CM.
    Largest segments are 42CM to 63CM.

    My foundling has tested both at Ancestry and 23and me. The 217CM has tested at Ancestry and if asked I believe she would supply the raw data file. So wonder if running David Pike’s analysis would give us any useful information.

    Regarding the other two clusters, one has only a common surname, the other has two common ancestor couples and we have not found connection between them due to lack of records.

    Thanks and regards


    • Hi Kathy,
      I really do not know how much endogamy is in the Haitian population but in my experience with endogamy you get one giant cluster so probably not a factor.
      I would suggest using the Are Your Parent Related tool at GEDmatch though, see https://blog.kittycooper.com/2018/07/when-the-dna-says-your-parents-are-related/
      Your large cluster has an explanation so build that tree and see if you can target test descendants of the other wives as your foundling is likely descended from one of them

      • Thank you Kitty for your reply. Parents are not related on the GEDMatch tool. We will continue to search for other wives.
        Thanks and regards

  22. Kitty,
    I have a question as I’m trying to help someone with ghihgly endogamous line as well as NPEs (I know it;s a fool’s erand). But the question is a general one. She has three matches with a family that I believe are at least her double fourth cousins. One of the lines contains a first cousin marriage. Her matches with these three who are a parent and two siblings are all 3 or 4 segments matches with totals of abt 100 cM range but each has a long segment of 60cM+. I know endogamy results in lots of chopped up segments. Is that what this long segment is? or is it truly along segment. Unfortunately, I can’t see the segment because the testers are on ancestry.com, but they report it as single long segments. The first cousin marriage is 4th great grandparents.

    • You might try and get them to all upload to GEDmatch or MyHeritage so you can see the segments. Tier 1 at GEDmatch will let you search for all the kits that match a specific segment… Yes pedigree collapse will increase the match sizes. My father has a double 5th cousin plus also a 6th who appears to be a 3rd cousin due to their first cousin grandparents… longer segments are usually closer family but occasionally a specific large segment will persist over generations.

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