So I’ve been delving into personal genetics after sending off for 23andMe testing, and last week I wrote about disease risk alleles. The medical stuff is obviously important, but I’m also keenly interested in my own ancestry as revealed by the 23andMe results.
Genealogy versus Genetic Ancestry
In case you were not already aware, I am a white guy. The self-reported ancestry in my family is mostly German, some Irish, consistent with surnames like “Koboldt” and “Meehan” in the family tree. Despite good genealogical work on both sides going back to the 1800’s, I hoped there might be something hidden in my genetic ancestry, some unexpected link to Native Americans or African tribes or British royalty.
Unfortunately, at first glance there was little to be excited about. According to my 23andMe results, I have 100% European ancestry, and the breakdown is pretty much what you’d expect:
The vast majority of ancestry-informative markers (AIMs, as they’re called) indicate nonspecific northern European origins for my family. Boring. On the bright side, the British/Irish ancestry is evident, if less than expected. Perhaps what surprised me most is that my perceived largely-German roots weren’t pinned down. Also, one can’t help but wonder how the Germans and French would feel about being lumped into the same category.
Maternal and Paternal Lines
One fascinating aspect of the ancestry stuff is how 23andMe traces your maternal and paternal lines, presumably using markers on the mitochondrial and Y chromosomes, respectively. I’m sure this would be more informative if my parents both underwent 23andMe genetic testing, which I’m trying to convince them to do.
The differences here are fascinating: my maternal lineage traces back to French Canada and Europe, while my paternal line is all over the place in Europe and Africa. Clearly we’re looking at ancient genetic history here, not the past couple hundred years. My paternal haplogroup, G2a, is a fairly common one. And I couldn’t help but notice, in the widget of “Haplogroups of famous people” on 23andMe’s site, that there’s another individual that’s part of the G2a family:
That’s right, folks, I’m related (in a very very distant sense) to royalty. King Louis XVI was the king of France for almost 20 years, married to Marie Antoinette, and eventually beheaded during the French Revolution. We share the same branch in the G2 haplogroup tree:
This also means — as long as the royal pedigree has no, shall we say, “inaccuracies” — that I also share the haplogroup of his great-great-great grandfather, King Louis IV, the Sun King, one of the longest-reigning European monarchs of all time. Calls to the Palace at Versailles to confirm this information were not returned.
Neanderthal Ancestry
Last but not least, 23andMe also looks at the less elegant side of the coin: how much DNA we share with Neanderthals, probably using data from the Neanderthal Genome Project. It turns out, about 2.9% of my genome came from these low-browed, hulking relatives of modern humans:
So I’m above your average European when it comes to Neanderthal DNA content, a fact that my parents are quite happy to attribute to each other. But hey, if it means slightly larger cranial capacity and broader shoulders, I’ll take it.
Fairly recent genetic evidence suggests that Neanderthals contributed about 1-4% of DNA to modern humans, probably by interbreeding in Europe between 80,000 and 50,000 years ago. That’s about the amount of genetic similarity that everyone shares with a great-great-great grandfather. So apparently, I’m as closely related to a Neanderthal as King Louis XVI was to the Sun King.