Have you ever heard the word endogamy? It is the way people within the same group marry over and over again. Some groups that have this issue are Acadian, Jewish, and Island populations, including Ireland. Another group of people it includes are those in isolated areas. An example are small towns where the same families have lived for generations. If you happen to have endogamy in your family line it may cause issues when you go to figure out how you are related to those relatives you have found doing DNA tests. Yet, there are workarounds to this issue which we will discuss below.
I have not so long ago ancestry in West Virginia. While working on my family tree I became so confused because the same family names kept popping up and marrying that I was convinced every person in this one area were all related somehow. Then I did a DNA test and I kept finding cousins with high centimorgans (cMs) but who were not, according to my research, that close a relative. Here is an example, you will usually share about 75 to 100 cMs with a third cousin but with endogamous roots could be as much as 250 cMs, which is more like the amount you would expect to share with a second cousin. So how can you work around these issues?
Endogamy makes your genetic relationship look closer than it is. You can work around this by either looking in your family tree and figuring out how you are actually related or if your testing company uses a chromosome browser to only count the shared segments that are longer than 15cM and use only those long segments when calculating your relationship. Do you use family grouping with your DNA matches? Family grouping relies on family lines being genetically distinct from each other. With endogamy your family lines are not going to be as distinct. You can work around this by once again looking at the best matches you have with the longest segments.
I know that I find DNA matching confusing sometimes. Then add in endogamy and it can be a long process of figuring out how exactly you are related to each other. Yet, if you are willing to take the time it can be very rewarding to figure it all out. When I was explaining it to my mom she said how long did this take you? My answer is not as long as those brick walls we have in our family history, more like climbing over a fence that is just a tad too tall to get right over. And it helps most that my husband is formally trained in genetic genealogy!
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If you need any help finding your ancestors, just let us know.
