"Finding Your Roots with Henry Louis Gates Jr." - DNA in The Fourth Episode

Last night PBS aired the fourth episode of Finding Your Roots with Henry Louis Gates Jr. which featured husband and wife Kyra Sedgwick and Kevin Bacon. The episode concentrated on exploring the couple's deep American roots, stretching back to the early days of the Colonies.

Husband and wife Kyra Sedgwick and Kevin Bacon

Unfortunately, there was very little genetic genealogy in this episode. At the very end, Dr. Gates presented Kyra with her DNA results explaining, "Using traditional genealogy, we were able to trace her father's line back hundreds of years...but using DNA Analysis we were able to go even deeper into her past on her mother's line establishing her Jewish ancestry genetically." First Dr. Gates showed Kyra a chart. In editing they inserted a shot of a chart illustrating the path of Y-Chromosome DNA which is passed down from father to son. Since she is a woman and they were discussing her mother's side, I believe that they were actually analyzing her mitochondrial DNA haplogroup which is passed from mother to child. The voiceover said that they were looking deep into the past of her mother's line, so she likely has a mtDNA haplogroup that is associated with Ashkenazi Jews.

Chart from "Finding Your Roots" showing the path of Y-DNA

Then they looked at a chart from 23andMe's Ancestry Finder and Dr. Gates explained, "Here's a graph of your 23 chromosomes and what it says is that 50% of all of your genetic material that they examined traces back to Ashkenazi Jews."  Note that he adds the qualifier "that they examined". This is because the Ancestry Finder feature only reaches conclusions about the portions of your DNA that have people who match it in their system, so most people do not have 100 percent coverage on this tool. Ancestry Finder is based on the answers that your DNA matches provide on the 23andMe survey "Where Are You From?" and, therefore, bases its analysis on the stated birth places of your matches' grandparents. (For more information on this feature, please see the post that I wrote about Ancestry Finder when it was first introduced.) The Ancestry Finder feature allows a user to click a box to see which of their matches have self-identified their grandparents as Ashkenazi Jews. For Kyra, this was apparently the case with approximately 50% of her total matches on Ancestry Finder. Instead of showing a screenshot of the graph of her "23 Chromosomes" which would have illustrated this result, they showed an image of her Ancestry Finder list of matching populations (seen below). This list of matching populations identified by Ancestry Finder also supports Dr. Gates' team's conclusion that Kyra has substantial Ashkenazi Jewish ancestry since the ones at the top of the list are typical in my experience for  those with Jewish ancestry.

Kyra Sedgwick's 23andMe Ancestry Finder from "Finding Your Roots"

At the end of the episode, Dr. Gates revealed to Kyra that her fear of being cousins with her husband Kevin Bacon was confirmed and that she and Kevin are 9th cousins once removed. Although fun for entertainment purposes, in the context of genetics, this is pretty meaningless since chances are that neither of them has any genetic material remaining from their shared ancestor(s). If they were to both test their autosomal DNA at 23andMe or with Family Tree DNA's Family Finder, they would likely not find any significant common DNA between them (unless they have closer yet unidentified shared ancestors). Since Dr. Gates team likely did test them both at, at least, 23andMe, I suspect my assumption is correct. This is because with each successive generation of random autosomal DNA inheritance, the contribution of each ancestor gets broken into smaller and smaller pieces and the majority of our ancestors have "fallen off of our genetic family tree" by the time you reach back past a couple hundred years. (Blaine Bettinger of "The Genetic Genelaogist"explains this concept here.) That is why autosomal DNA tests for genealogy like 23andMe and FTDNA's Family Finder work best for researching more recent ancestry.

I am looking forward to next week's episode with Rick Warren, Angela Buchdahl, and Yasir Qadhi and hope to see more integration of genetic genealogy. In the preview, I caught a glimpse of my friend, 23andMe's geneticist Mike Macpherson (one of the creators of Ancestry Finder). I can't wait to see his appearance on the show!


I have been writing a review of the DNA testing used in each episode:
Week 1 - Episode 1 and Episode 2 - Harry Connick Jr. & Branford Marsalis; Cory A. Booker & John Lewis
Week 2 - Episode 3 - Barbara Walters & Geoffrey Canada

Update: 23andMe's New v3 Chip Results Are In

Today there is a lot of excitement in the personal genomics community because 23andMe's eagerly awaited v3 results are finally coming in. The customers receiving their results today are ones who bought their kits near the beginning of the last holiday sale. Making it even more exciting is that, according to 23andMe, they are loading thousands of data sets today in this first round. Apparently, they had a very good response to the last sale. This is very good news for customers who are interested in the ancestry aspects of their genetic scans. Judging from this, over the next month, the number of potential "cousins" should jump substantially from the approximately 60,000 records already in their database.

So far, my health results, Ancestry Painting and U5b1b2 mtDNA haplogroup assignment look identical to my v2 results. I am still waiting for my Relative Finder and Ancestry Finder to load. However, I am hearing that some customers have revised and, apparently, improved Ancestry Paintings as well as updated haplogroup assignments.

Giving a little insight into what changes we can expect, Michelle K from 23andMe posted this in the 23andMe Forums on January 19th:

"The first batch of v3 results will become available by the end of this week. Please note that v2 data will not be overwritten by v3 data, rather the two will be merged into one data file. Here are some changes you can expect to see:

RelFinder and Family Inheritance: The Relative Finder algorithm has been updated. Customers who upgrade to v3 may notice small changes to their percentages DNA shared or segment locations in Family Inheritance. Existing, not-yet-upgraded customers may also see small changes to their results as their relatives upgrade.

Ancestry Painting: The Ancestry Painting algorithm has been updated. Upgrading customers may notice small changes to their percentages. Existing, not-yet-upgraded customers will not be affected.

Haplogroups: Upgraded v3 customers may see a slight change in their haplogroup due to updated haplogroup trees and v3 compatibility. The change, if any, should be very minor -- only affecting resolution and not affecting major group assignments. All other existing customers will have their haplogroups recomputed on the new trees later this year. This means, for example, if a child is analyzed on v3 and their parent is on v2, they may have different haplogroup assignments.
Raw data: Upgraded v3 customers may have data for v2 SNPs they previously had no-calls for, if the SNP is on v3 and it yielded data. A complete list of v3 SNPs is expected to be available in the Mendel example profiles by mid-February."

I will be posting all week with updates about the new v3 results, so stay tuned...

"Ashkenazi and Me": Making a case for the Euro DNA Calculator application using ancestry analysis tools from 23andMe

Some time ago, I ran my raw 23andMe data through the Euro DNA Calculator Application. (Euro-DNA-Calc, compiled by Dienekes Pontikos, computes an admixture estimate with Northwestern European, Southeastern European, or Ashkenazi Jewish parental populations. The calc uses 300 markers from a scientific study.)  I was surprised to find that it estimated 86% NW European and 14% Ashkenazi for me.

My Euro-DNA-Calc Chart

Interestingly, my mother showed no Ashkenazi at all in her results with a 100% NW European prediction. Since I have no known Jewish heritage, after some research into the application, I disregarded it.

When 23andMe's Ancestry Finder was launched and began noting Ashkenazi segments, I noticed a spot on my Chromosome 7 that appeared to have a clump of self-declared Ashkenazi matches. When 23andMe started providing the download of the matches associated with Ancestry Finder, I saw that I had no less than 21 "Ashkenazi" matches on Chromosome 7 between 53.3m and 94.3m. My mother had none. These matches all appeared to be rather small and only on that one spot, but it did get me thinking about the possibility of distant Jewish ancestors again.

My Ancestry Finder chart set at 1 Ashkenazi grandparent

Since my father is deceased, I asked my paternal uncle to test in his place. Yesterday, I received his results. There, clear as day, on his Chromosome 7 appears that same Ashkenazi clump that I have (plus a little more: he has 37 self-described Ashkenazi matches on Chromosome 7 on the Ancestry Finder download).

Paternal Uncle's AF chart set at 1 Ashkenazi grandparent

Paternal Uncle's AF chart set at 4 Ashkenaki grandparents

Equally as significant, I could immediately see that he has a number of Public Matches in Relative Finder who list their ancestry as Jewish. Most of them are predicted as "Distant Cousin", which probably explains why they didn't show up in my Relative Finder. In this case, testing just one more generation back revealed very useful information.

While this Ashkenazi ancestry is clearly quite distant, it certainly appears to be authentic after all. Although the Euro DNA Calc greatly overestimated the likely percentage, it does seem to have picked up on legitimate Ashkenazi markers in my DNA.

Bravo, Dienekes!