Field of Science

My Dodecad identity-by-state neighbors.

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?

Edited to add photo evidence. Separated at birth, obviously. Dude, Snooki doesn't even have brown eyes.


  1. shouldn't u mention that snookz was adopted from chile?

  2. If I'm not, why is my phenotype so misleading?

    human phenotype spaces has only so many degrees of freedom. so there's a fair amount of convergence. e.g., the half-chinese/half-african american person who is confused for mexican or something.

  3. hah! I would have mentioned it if I had known it. I don't actually watch Jersey Shore, you know. Who does that? ;)

  4. Snooki doesn't even have brown eyes.

    LOL, those are obviously contact lenses, she does have brown eyes of course.

  5. hahaha. Now that you point it out it is kinda obvious.

  6. Michelle,

    For someone who doesn't mention having any Irish ancestry, you seems to be getting a good few Irish hits. I've seen this previously with Southerners, and one explanation is that Irish Catholics from Northern Ireland - especially Donegal - followed their Scots-Irish Presbyterian neighbors to the US, and over a few generations assimilated as Scots-Irish, and forgot/ignored their native Irish roots.

    Also, do you have a family history of any French Huguenot lines? My Mother DOD099 is getting a bunch of French matches.

  7. Hi Paul, my maternal grandpa is actually half Irish. Two of his grandparents were immigrants, iirc, and I also have several more distant lines that trace back to Ireland as well. I just don't often distinguish between Irish/Scotch/English/Welsh lines, preferring the general term British (it's easier).

    I believe I've mentioned before that I'm a carrier of hemochromatosis, of which I know the Irish are particularly afflicted. My guess is that I got it from him.

    As for Huguenots, I have no idea. I have a minority of ancestry lines that trace back to France but I know nothing else about them.

  8. I suppose I should explain that using British is easier for me because I don't personally put a lot of value in distinguishing between countries in the British Isles. I understand it probably matters a lot more to the people who live there or who have more pure ancestry than I do. :)

    The aforementioned half-Irish grandfather is also a ginger, btw.

  9. Michelle,

    Makes sense.

    FWIW, I don't think you look like Snooki in the image above, but more like Julia Roberts:

  10. The Snooki thing was a joke! Must have been a poor one, though, since nobody seems to get it. :)

  11. Michelle,

    I didn't get the joke then :(

    I've never watched Jersey Shore myself, but here's a link for Razib and your edification:

    Jersey Shore Gone WILDE:,55071/


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