Not Khan, though

Lynn, I remember that story. I think there was also a story - maybe in the NYT - about some guy who turns out to be descended from Genghis Khan, and they figured it out from his DNA. (And it is entirely plausible that lots of common folk are descended from royalty, both the time-elapsed-since-then thing and also the fact that a lot of them had a lot of kids, and also a lot of "wrong side of the blanket" kids)

It still amuses me, though. (I figured my family would be farmers/peasants all the way down.)

I also have an example I use for the DNA fingerprinting stuff I teach in general bio; there are the remains of a 9000 year ago man from Cheddar, England, and when they sequenced DNA of people in the surrounding area, they found a schoolteacher who was apparently a direct descendant. That at least some thread of the family lived in that area for 9000 years is pretty amazing.

There used to be a company where you could send off a cheek swab and they'd tell you which (supposedly) of seven matrilineal lines you came from in Stone Age Europe. (There's a book out called the Seven Daughters of Eve that addresses that). I assume I'd come up as either "Celtic" or "Gaulish" (if those were in fact designations, I don't know what groups they talk about as having been the seven tribes*). But I was too cheap to cough up the $150. It would be interesting, but not particularly useful, knowledge.

(*Actually, they don't. They don't use any of the old ethnic designations, probably because they didn't exist in the Stone Age. Instead, they give hypothetical names to the women: mt DNA and human migration. If I had to guess, I'd say I was most likely a descendant of "Helena," but of course I don't know for sure. And I admit a little bit of annoyance with the cutesiness of "naming" those hypothetical women.

That same website references "Irish with Spanish heritage" - which, for years, people have spoken of "Black Irish," that is, Irish people with very dark hair, and there was hypothesized that shipwrecked sailors from Spain had come ashore and intermarried.)