Watch out for what "Genetic Ancestry" might be telling you!

In my last couple of posts dealing with playing with my 23andMe genome data, I have been exploring genetic ancestry and having a giggle at the numbers that come up. We need to treat these numbers with a certain degree of perspicacity - they don't necessarily mean what first glance would imply. This is not new information - here is Joe Pickrell's blog post on Genomes Unzipped from 2010 dealing with the prediction that he had 20% Ashkenazi ancestry. Further poking suggests that he probably doesn't, but the story of how we can interpret these data is very informative. Highly recommended!