On the curiosity of genes and genealogy
Wed, Feb. 17th, 2016 08:10 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
scarlettinaNote: This is an expansion of a Facebook post. In an effort to get myself back on the LJ wagon, I'm taking a shortcut of sorts.
I'm a regular watcher of Finding Your Roots on PBS. After tonight's extraordinary episode (Season 3: Family Reunions), I went to the site and found a fascinating article on Jewish genetic genealogy that explains some of the baffling results from my Ancestry DNA test: namely, that thousands of potential family matches showed up. Some of this may be due to the fact that my maternal great grandfather was the father of 23 children (between two wives; yes, really). But that can't account for all those results.
It turns out that the reason for those thousands of results isn't the fact that Great Grandpa Pinchus was prolific. It's that "working with Ashkenazi Jewish autosomal DNA (atDNA) for the purpose of cousin matching has unique challenges due to the fact that the ancestors of Jews today have historically been an isolated population, typically marrying within their own group. The resulting lower degree of genetic variation means that any two people of predominantly Ashkenazi Jewish ancestry are likely to share stretches of matching autosomal DNA that would usually imply recent common ancestry between them, but the genealogical relationship is most often untraceable. This is because rather than a single recent common ancestor contributing this matching atDNA, it was inherited from multiple, more distant ancestors. The contributions from these multiple shared ancestors can add up to enough shared atDNA to mimic a relatively close cousinship."
Technically speaking, this means that Jewish genetic cousin matching is very difficult indeed. Those thousands of matches I received may not actually be relatives at all. Though the Ancestry DNA test results include a lot of information about the results and the test methods, they don't explain this particular issue. Disappointing. Intuitively, the information in the quote above does make sense. And, in fact, after investigating 20 or 30, I have found almost no one who shares surnames with me, or has trees that even might touch mine. I just uncovered one surname that might be a match, but it's a fairly common name (Schwartz) in the wrong part of the European map. I'll still write them; anything is possible. It's on a branch of the family that I have very little information about that's not anecdotal. But it's one out of thousands.
The above-linked blog post explains my voluminous results. It's a little disheartening, I admit. I had hoped for some contact with other descendants of Great Grandpa Pinchus. I may yet have one more route for investigation and when I have time (that copious "spare time" of myth and legend) I want to pursue it.
It's interesting stuff, though. The article is fascinating, even if you're not Jewish, and well worth the reading.
I'm a regular watcher of Finding Your Roots on PBS. After tonight's extraordinary episode (Season 3: Family Reunions), I went to the site and found a fascinating article on Jewish genetic genealogy that explains some of the baffling results from my Ancestry DNA test: namely, that thousands of potential family matches showed up. Some of this may be due to the fact that my maternal great grandfather was the father of 23 children (between two wives; yes, really). But that can't account for all those results.
It turns out that the reason for those thousands of results isn't the fact that Great Grandpa Pinchus was prolific. It's that "working with Ashkenazi Jewish autosomal DNA (atDNA) for the purpose of cousin matching has unique challenges due to the fact that the ancestors of Jews today have historically been an isolated population, typically marrying within their own group. The resulting lower degree of genetic variation means that any two people of predominantly Ashkenazi Jewish ancestry are likely to share stretches of matching autosomal DNA that would usually imply recent common ancestry between them, but the genealogical relationship is most often untraceable. This is because rather than a single recent common ancestor contributing this matching atDNA, it was inherited from multiple, more distant ancestors. The contributions from these multiple shared ancestors can add up to enough shared atDNA to mimic a relatively close cousinship."
Technically speaking, this means that Jewish genetic cousin matching is very difficult indeed. Those thousands of matches I received may not actually be relatives at all. Though the Ancestry DNA test results include a lot of information about the results and the test methods, they don't explain this particular issue. Disappointing. Intuitively, the information in the quote above does make sense. And, in fact, after investigating 20 or 30, I have found almost no one who shares surnames with me, or has trees that even might touch mine. I just uncovered one surname that might be a match, but it's a fairly common name (Schwartz) in the wrong part of the European map. I'll still write them; anything is possible. It's on a branch of the family that I have very little information about that's not anecdotal. But it's one out of thousands.
The above-linked blog post explains my voluminous results. It's a little disheartening, I admit. I had hoped for some contact with other descendants of Great Grandpa Pinchus. I may yet have one more route for investigation and when I have time (that copious "spare time" of myth and legend) I want to pursue it.
It's interesting stuff, though. The article is fascinating, even if you're not Jewish, and well worth the reading.
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Date: Thu, Feb. 18th, 2016 02:14 pm (UTC)I've taken a step to better approach that myth and legend. I've resigned from my current job (many are calling it "retirement" but I'm not quite ready to use that word). Soon, I will have time, for example, to watch a number of episodes of "Finding Your Roots" that reside on our DVR and haven't been touched. (I enjoyed the show in previous seasons and look forward to this season, and your comments only supported that.)
I know a lot about my dad's side of the family but relatively little about my mom's side. I do know there was cousin intermarriage and a secret aunt I didn't learn about until after mom's death. I hope to have the "spare time" to delve into my family some more. Thanks for the nudge!
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Date: Sat, Feb. 20th, 2016 03:56 pm (UTC)Resigned for your job? I won't call it retirement if you don't, but I hope you enjoy the down time! I find "Finding Your Roots" fascinating, well worth the time invested in watching. This week's episode, in particular, was just terrific!