Second, Dienekes followed up on his analysis of the ancestry of the GNZ participants with a much larger data set, including individuals of southwest European descent. As expected, when including more data, there was no evidence that Vincent has any Ashkenazi ancestry. Unexpectedly, this was not true for me—even in this larger analysis, the evidence for Ashkenazi ancestry didn’t disappear.
As I was mulling over these sorts of issues, I sent the link to my previous analysis to a family member. I didn’t really expect this person to find it that interesting, but hey, you never know. I then got a phone call. I’ll summarize a couple days worth of moderate confusion, second-hand reports of conversations with distant relatives, and family intrigue with this: as it turns out, one of my great-grandparents was indeed a Polish Ashkenazi Jew who immigrated to the United States around the turn of the century. I, obviously, was completely unaware of this.
So to conclude, a tip of my hat to Dienekes and everyone else who looked at these data—this has been the first genuinely unexpected thing to come out of my genetic data.I've estimated Joe's ancestry here and here.
He is included in the Dodecad Project's spreadsheet as JKP001.
His "Southwest Asian" score of 6.7% is consistent with but not indicative of Jewish ancestry, as this component is found in West Asia and Europe, although it attains its maximum in Saudi Arabia and occurs at about 20% in European Jews.
So, while I wouldn't conclude that he had partial Jewish ancestry based on his data, the issue is no longer relevant due to the emergence of the new genealogical information.
This is an example of what I called "cryptic ancestry" as a possible explanation for people getting unexpected results.