Dienekes recently computed an identity-by-state (IBS is his abbreviation, although that means something very different to me) similarity matrix for all the individuals in the Dodecad Ancestry Project. The IBS score is a ratio between individuals that, to my understanding, can be read as a proxy for genetic similarity.
He also posted an R object that you can download to find your closest IBS neighbors. I ran the program for myself (DOD493) and added the ancestry of DOD participants that have posted in the ancestry thread. In the interest of saving space, I have removed all the DOD samples that have not disclosed their ancestry (you can see which ones are missing in the “Rank” column). Click to enlarge:
Not much here surprises me. Most of my neighbors have at least one of my ancestral components (British, German, and French). Obvious exceptions are the two Lithuanians, the Spaniard, the Scandinavian, and the Belarusian. My guess is that the Eastern Europeans have unstated Western European admixture and that the Spaniard probably has French admixture specifically.
Something I do find a bit puzzling is that I don’t seem to have much genetic similarity with Italians. This has been puzzling me all throughout, ever since I began trying to decipher my own admixture. All through my adult life I have been approached by strangers at the bus stop or in restaurants to tell me that I look identical to their Sicilian (always Sicilian for some reason) niece/grandma/whatever. (I think this may just be the nature of Italians, that they like to seek out their own kind. I’ve never had someone come up to me and tell me I look like I belong to any other ethnic group.) I expected to find some Italian admixture, probably on my paternal grandmother’s side, just because so many Italians seem to think I’m one of them. If I’m not, why is my phenotype so misleading?