Monday, April 16, 2012

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


The fifth episode of Finding Your Roots with Henry Louis Gates Jr., which featured religious leaders Rick Warren, Angela Buchdahl and Yasir Qadhi, aired last night on PBS. This means we are halfway through the miniseries! As we have progressed through the episodes it appears to me that Gates and his team are featuring DNA testing progressively less and less. This is a shame and I hope this trend will reverse itself in the second half of the season.

The DNA portion of the show last night comprised only about 5 minutes (starting at 44:55), but drew some interesting genetic comparisons between guests of different religious backgrounds, demonstrating again that DNA testing is "deconstructing the notion of race" (quote from Gates in an earlier episode). Qadhi's Y-DNA haplogroup or what Gates referred to as his "paternal haplogroup" which was inherited from his father's father's father, etc... is J2. This haplogroup is common among those with Indian ancestry like Qadhi, but also "reaches levels of about 20% in Ashkenazi Jews". Qadhi said that he didn't find this too surprising since "Muslims and Jews consider themselves cousins...(as) descendants of Abraham."

Yasir Qadhi reviewing his Y-DNA Haplogroup

Qadhi also had a surprising "matrilineal cousin" in a guest from an earlier episode -  Barbara Walters - with whom he shares his mtDNA haplogroup which was inherited from his/her mother's mother's mother, (etc...). Unfortunately this haplogroup was not revealed in either episode, so we can only guess what it may be. I would imagine that in each case, while sharing the major haplogroup, Qadhi of Indian ancestry may belong to a slightly different subclade than his Jewish cousins. (See the Y-Haplogroup J Project for details.)

Less surprising, Rabbi Buchdahl is also a distant cousin to Barbara Walters. Gates said that Buchdahl and Walters share a common ancestor within about the last 300 years. He mentioned "three segments" in common between them. This test was clearly an autosomal DNA test by 23andMe or Family Tree DNA's Family Finder. Normally three matching segments of DNA would imply a significantly closer relationship than distant cousins, but among the highly endogamous Ashkenazi Jewish population, this is not uncommon. I was pleased to see Gates team incorporating all three types of DNA used for genealogy in this segment.

Angela Buchdahl reviewing her father's Warnick Y-DNA (?)

In the voiceover starting at 46:15, Gates explains, "DNA Analysis can tell us...where our earliest ancestors originated thousands of years ago, to whom we might be related today and the percentages of our African, European and Asian ancestry over the past 500 years." I thought that this may have caught some viewers' interest, so I wanted to detail which tests he was referring to in that comment.

The first part of the quote - "where our earliest ancestors originated thousands of years ago" -  refers to deep ancestry that is revealed through our Y-DNA and mtDNA haplogroups, tracing the migration of mankind. You can learn your haplogroups from 23andMe's DNA test or by taking the Y-DNA STR test and/or the mtDNA test at FTDNA.

Next, "to whom we might be related today" refers to autosomal DNA tests that match you with cousins from your more recent ancestry by examining matching blocks of DNA between testers. These types of autosomal tests are currently only offered by 23andMe and FTDNA. 23andMe's "Relative Finder" feature is included in their single test and FTDNA's test for this purpose is called "Family Finder".

Lastly, "the percentages of our African, European and Asian ancestry over the past 500 years" refers to biogeographical ancestry analysis or admixture tools like 23andMe's Ancestry Painting or FTDNA's Population Finder. In this case, he was specifically referring to 23andMe's Ancestry Painting. This is the most basic of genetic ancestral origin tools only using the three populations mentioned. FTDNA's Population Finder breaks down genetic origins into more granular populations and 23andMe's Ancestry Finder feature does so as well, with a somewhat different approach.

Earlier episodes have shown the pie chart with the guests' ancestral origins or genetic admixture by percentages. In this episode, we caught a glimpse of Pastor Rick Warren's dark blue chart, signifying 100% European. While he and Gates laughed at this result, it isn't necessarily as boring as it might sound since, in this case, "European" encompasses ancestry from all over Europe including Russia, France, Germany, Finland, the British Isles, the Middle East, Scandinavia and many other countries.

It would have been interesting to see all of the guests' Ancestry Paintings in this episode because there would have been much commonality between them. As a person of Indian heritage, Qadhi would have likely possessed a large European component and a smaller Asian one and Buchdahl's chart, being half Jewish and half Korean, would have probably been equally split between Asian and European. (Upon further review of the episode, it appears that I was correct - see below.) The specific differences between the Asian and European ancestry among the guests would only be revealed with a more detailed breakdown, such as FTDNA's Population Finder or 23andMe's Ancestry Finder.

Angela Buchdahl looking at her "Ancestry Painting"

Next week we will be privy to details of the family trees (and hopefully DNA!) of movie stars Robert Downey Jr and Maggie Gyllenhaal. That sounds like fun! See you then...


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

Week 3 - Episode 4 - Kevin Bacon & Kyra Sedgwick

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