Is it endogamy or an NPE? DNA test results

Question

My recent Ancestry DNA test shows that I have matches ranging from 10-30 cM with about a dozen descendants of a man named Elias Hasbrouck (c. 1741-1791) of Kingston, NY. Elias is not one of my paper trail ancestors, and I'm confident both in the existing paper trail and in the fact that there aren't any gaps where he might fit in. That leaves two possibilities: Either someone in Elias' line or one of my ancestors had a different father than the paper trail indicates, or this cluster of matches is the result of endogamy.

Looking at Elias' tree (https://www.wikitree.com/wiki/Hasbrouck-85), I can see that I'm a descendant of two of his grandparents and of ALL of his great-grandparents, some of them by multiple lines. (I descend from his Deyo grandparents seven or eight times).

Most of my matches with Elias' descendants are through his son, Daniel Elias. His mother, Elizabeth Sleight (Slecht), is also a relative. I descend from six of her eight great-grandparents. Two of these great-grandparents were sisters (Marie and Elizabeth Blanchan). Both are my ancestors, and I also have multiple other additional lines of descent from their parents via another sibling.

So... is there enough endogamy going on here to potentially explain this set of matches, even though the common ancestors are in the early 1700s and 1600s? Or is that just not possible, in which case I need to start combing my tree and Elias' for any possible place where an NPE might have happened?

Comments

Jim, it would be easier for members to advise you if you would complete the process of joining WikiTree (currently you are just a guest member) and add profiles for your ancestors on the relevant line(s). If you do that, we could visualize how you are related to Elias Hasbrouck (WikiTree has some amazing tools for tracking relationships).

It's definitely not impossible that these DNA matches are due to shared ancestry on the lines you know about, particularly in view of the endogamy you describe.

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Thanks! I hope to add my tree to WikiTree in the future, but I need to add a lot of sources to my file first. In the meantime, I ran a comparison between Daniel Elias Hasbrouck and myself in my genealogy program's relationship calculator. He is my:

• 2nd cousin 8x removed
• 3rd 8x
• 3rd 7x
• 3rd 7x
• 3rd 7x
• 3rd 8x
• 3rd 8x
• 3rd 9x
• 3rd 8x
• 3rd 8x
• 3rd 8x
• 3rd 8x
• 3rd 8x
• 3rd 7x
• 3rd 7x
• 3rd 7x
• 4th 7x
• 4th 7x
• 4th 7x
• 4th 8x
• 4th 8x
• 4th 7x
• 4th 7x
• 4th 8x
• 4th 8x
• 4th 7x
• 4th 7x

Basically, the families lived in the same small town for 200 years, and the descendants of the 12 founders kept marrying each other.

Answer 1

I don't think it needs to be endogamy or an NPE, could just be that you inherited the same bits from shared ancestors.  10-30cm bits could easily be explained only by this: 

I can see that I'm a descendant of two of his grandparents and of ALL of his great-grandparents, some of them by multiple lines. (I descend from his Deyo grandparents seven or eight times).

& - what Ellen said, recommend you add these profiles to your tree so we can get a better look.

Comments

Thanks. See reply above for adding my tree and the details of my various paper trail connections to Elias and his son Daniel Elias. What has me curious is that I don't have this number of genetic matches with descendants of any other individual person -- let alone one that I'm not descended from according to the paper trail. But, obviously, there are a lot of paths for DNA to have traveled!

Answer 2

I have a dozen matches in the range 10.7cM to 29.0cM to descendants of an ancestral couple who were both born around 1700 - 6th-great grandparents! I don't think you have any cause for concern, at all.

I also have a group of over SIXTY-FIVE matches that go as high as 36cM, for descendants of some ancestor back well beyond my gt-gt-gt grandfather. Many of them are on disparate branches of a family that started with a single couple who married in NC in 1791. My own ancestry was never south of Baltimore, MD - I believe it goes back to a common (unknown) ancestor earlier on who migrated from West Jersey (or thereabouts) to NC back in the mid 1700s.

Members of this 65+ absolutely DOMINATE my GEDmatch results.

Something everyone here should become aware of is the so-called "Sticky Segment" phenomenon. This is where, for reasons not well understood, a segment "sticks together" for much longer than you would normally expect. I prefer the explanation that these are segments that have simply "beaten the odds", and that everyone generally has a handful of these.

I have another one that clearly goes back to a 5th-gt grandfather (conveniently, he had two wives, and a descendant from the other wife is among the matches!) There are 70 matches in THAT group - it was an extremely prolific family.

Such a segment can be as big as, perhaps 50cM. I have a match to a guy which is 50cM, and only a single segment. I don't know exactly how he's related, but someone else who matches him, and has a 46cM match to me (again, one a SINGLE segment) is descended from my gt-gt-gt grandfather (It's clear from other matches that it's NOT from his wife). Unfortunately, there's only a handful of matches, outside of my closer relations, who also have it.

Obviously, if you have some huge 50cM segment from WAY back, you're going to match a large number of distant relations who themselves only have a small piece of it.

My own pet theory is that these tend to follow along paternal lines, because the recombination rate is noticeably lower for males. My group with 70 in it has only ONE female ancestor in the lineage. My lineage to the 50cM segment also only has ONE. I'm pretty sure my 65+ group goes back to an ancestor of my gt-gt-gt grandfather who is straight up my paternal line.

Personally, I'd prefer to call it a "super segment". "Sticky" just sounds silly - and icky.

Comments

Thanks Frank Stanley!

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Yep, I have a similar cluster of matches with descendants of a set of 6th great-grandparents who match to me and my mother for between 15 and 40cM. There are 40 people on GEDmatch who share some or all of this 40cM segment. Interestingly this is through two daughters of James and Eleanor Douglas, born c. 1740 in Northumberland, England; my line to the common ancestor passes through four females, including my mother (and a significant number of shared matches also have four female generations between them and the MRCA).

And my mother has another cluster of matches (on GEDmatch and Ancestry) in the range of 15-37cM, who are all descendants of Robert Tyler and Susannah Duvall (her 7th great-grandparents); her line to these MRCAs passes through six generations on the direct male line and then two generations of females. So whether direct male lines make a difference in recombination seems to be a matter of chance as much as anything and some of that may be confirmation bias.