With 23andMe’s new update to its ancestry, the results for my family have changed. Not for me, since I’m not of European descent, and this looks Euro-focused (no surprise). But my wife and kids are different.
My wife has two great-grandparents who were born in Norway. 23andMe is picking that up immediately. It also picks it up in my children, from left to right, my daughter, my younger son, and my older son. With more than 3 million in their database 23andMe has knowledge of which haplotypes are unique to Norway, and which are not. When you click “Norway,” it says “We predict you had ancestors that lived in Norway within the last 200 years.” That’s telling me that they detect IBD segments uniquely found in Norwegian populations of a particular length threshold.
My youngest is on a new chip, so the Western Asian & North African I dismiss. But I’m not sure I believe some of the European admixture estimates. The two boys exhibit very little drop off in Scandinavian. But my daughter is way lower. This is not unreasonable, but they also exhibit differences in East Asian ancestry. And I’ve looked but I can’t detect this on PCA plots. My daughter is, in fact, more distant from Han Chinese than my sons.
In the future, I think perhaps genealogy-focused results, which show matches within particular nations, should be partitioned from admixture analysis. That’s how it used to be.
(it is a curious coincidence that both my more Scandinavian children are heterozygotes on the KITLG locus for the derived variant, though I know they get it from their mostly German grandfather)