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Endogamy and DNA

Feb25

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.

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DNA transfers to Family Tree DNA are back!

Feb16

It’s working again! At last …

You can upload your DNA test results from Ancestry.com and/or 23andme to Family Tree DNA again! You get a free look and then can pay a mere $19 to get all the tools and information.

Click here for an old blog post of mine for help on getting your DNA data and transferring it. You have to be logged out of any account you have there with family finder results (mtDNA and Y are OK), before you upload. First you sign up for a new username and password (each test result has its own log in). Also be sure to use the zipped download of your data.

I recommend that you download your raw data again to do this. When I rezipped an old ancestry file and tried it, I was told that it was the wrong format but when I downloaded it again, the new version worked just fine.

Click here for more details at Roberta’s blog.

23andMe News: A Sale and New Features

Feb8

There is a Valentine’s Day Sale at 23andme.com for American users, $20 off for up to two kits until Feb. 14 which brings down the price for the ancestry only version to $79, more in line with the other companies.

In other news, rumor has it that non-American users will finally be transitioned to the new experience in the next few months. If anyone from 23andme is at Rootstech this week, I will ask for more specifics on that.

Meanwhile there are several new features at 23andme for those of us, Americans, on the new experience:

  1. The automated triangulation feature now shows all DNA relatives, not just open sharers, and includes anonymous users with a link to request a share.
  2. Ancestry composition includes a timeline indicator making a guess as to when your ancestor with that ethnicity might have lived.

Click the read more for the details on these. I confess, I am at Rootstech right now, so not there is not much time to write about these in depth, just a few thoughts and images.

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DNA Triangulation 2017 – My Rootstech Talk

Feb2

Rootstech is almost here and I can’t wait. It is not just the great talks that I love but also all the wonderful displays, shows, and tools in the exhibit hall and, of course, seeing old friends. Naturally I am going in a day early to spend time in that wonderful Family History Library, practically next door to the conference!

My talk is about triangulation, a technique used with DNA test results to prove descent from a common ancestor. I hope to see you there, Thursday at 11:00 in the morning in Ballroom J. As always my slides will be posted at slides.com/kittycooper after the presentation.

Wold line cousins Kitty (me), Ed, Marlys

If you have been to previous versions of this presentation, there will be much that is new this time around. It is amazing how much the DNA technology for triangulation has progressed in just a year. Most American 23andme kits are now on the new experience which includes an automated triangulation feature. Plus GEDmatch has added Triangulation Groups (TGs) to its Tier 1 tools.

Furthermore one of the semi-finalists in the RootsTech 2017 Innovator Showdown is a new Double Match Tool from Louis Kessler that provides triangulation for different ftDNA kits that you have the Chromosome Browser Results (CBR) for. Click here for his blog and description of DMT. Genetic genealogy has come a long way!

There is also news for those of you who remember the story of how I used triangulation to confirm a thin paper trail and prove that Kristine is my Wold side cousin (click here for that blog post and here for the follow up). The DNA test for Marlys, one of Charlie’s 26 grandchildren, came in and provides further proof. Not only that but Marlys had known the story all along about that first child of Charlie’s!

A Jewish Adoptee Finds His Birth Family

Jan30

This is the story of how I helped a Jewish adoptee find his birth family using DNA testing.

DNAadoption.com helps adoptees with DNA, including classes

First, here is a simplified explanation of the technique that an adoptee uses to find his birth parents using DNA:

  1. Do an autosomal test at each of the main companies. Once the results are in …
  2. Look through the family trees of 2nd, 3rd, and 4th cousin DNA matches for a common ancestral couple or two.
  3. Build private, unsearchable family trees down from each common couple to find someone in the right place at the right time.
  4. Get other people on those lines to test when their results will narrow it down some more.
  5. Males can also do a Y DNA test which might give them a surname if there are any close matches.

Obviously the more you know about the birth parents the easier this is. For more details on this technique see http://dnaadoption.com/index.php?page=methodology-for-autosomal-results or sign up for a class there.

Sadly these DNA search methods do not work well for adoptees from endogamous populations, such as Ashkenazi Jews (AJ) because everyone in that group shares as much DNA with each other as a 4th or 5th cousin. Even worse, most Jewish family trees stop at the grandparents or great grandparents because they do not continue across the ocean. Another problem is that even second cousins can have different Americanizations of their original surnames and let’s not forget that surnames are very recent in this population, about 1815 for most.

That is why there are so very few jewish adoptee successes, so I am celebrating this one with a blog post.

The DNA Search Story

I got an inquiry from, let’s call him Roger Stein, an adoptee curious about his birth parents who matched a cousin of mine at GEDmatch. GEDmatch is a site where you can compare tests done at different companies. His story follows, with all the names changed for privacy. If you do not want the DNA details just skip to the section titled “Contact.”
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