The Science of Admixture Percentages (Garrett Hellenthal)

As DNA collections continue to emerge, representing individuals sampled from ever more locations, genetic ancestry testing companies are able to provide increasingly precise and detailed information about customers’ ancestry. Typically these companies compare customers’ DNA to that of individuals sampled from different geographic locations, and then provide percentage breakdowns reflecting which of these locations contain a similar genetic make-up as the customer. But what do these percentages mean? Garrett Hellenthal explains some of the methodology behind the numbers, including recent computational advances, and discusses how to interpret (and how not to over-interpret) the results.
Garrett Hellenthal
Garrett Hellenthal is a statistical geneticist at University College London, whose primary work involves identifying the factors that contribute to the genetic variation among worldwide human groups.
This lecture was presented at Who Do You Think You Are? - Live! 2017. Please note that these videos are copyrighted to the presenter and should only be used for personal study. They are not to be used for any other purpose without the presenter's express permission. Also, please note that because this is a rapidly advancing field, the content may quickly become outdated.
The DNA Lectures were sponsored by FamilyTreeDNA (www.ftdna.com) and organised by volunteers from ISOGG (International Society of Genetic Genealogy, www.isogg.org). ISOGG volunteers also provided free DNA advice and support for members of the public at the conference.

[@maureenpainter7242]

Thank you to Garrett H and Maurice G for this lecture. Wow! This explains a lot about the ethnic percentages and how interesting they are but how difficult for us laymen to interpret really. My Dad is frustrated because his paternal line is all German from his great-grandfather on back...no German in his ethnicity estimate though. I can now explain why that happens better than before. I will have to watch the presentation again to let it soak in...

[@DNAandFamilyTreeResearch]

Unfortunately we are competing with 10,000 people in the arena! Audio is always less than what we would desire at WDYTYA. Sadly, this is the last year of WDYTYA as it has been cancelled. Hopefully there will be some replacement event in the UK in the future. But this is the final series of WDYTYA videos to be published.

[@LynetteDenise]

Thanks so much for this presentation! Answers so many questions!

[@beckyjohns5350]

Which country MTDNA haplogroup H3b2 origin came from?

[@BrittBeeMcGee]

The audio is horrid. I’d love to listen, but unfortunately i cannot. Sad, seems this guy is quite possibly the only one on UA-cam to even seem to know what he’s talking about.

[@bigfootpegrande]

May the ghost of Mendel show some silence and humility to all these clueless talking people in the background...

[@beckyjohns5350]

I know that I don't have 1,000 ancestors.
Some of the cousins got married to each other.