Semitic Duwa
בלי עין הרע
- Messages
- 207
- Reaction score
- 29
- Points
- 0
- Ethnic group
- Half-Jewish (paternal) & Half-British (maternal)
- Y-DNA haplogroup
- J1-Z18271 (Kohen)
- mtDNA haplogroup
- J1c5
Exactly so.
Admixture, and PCAs for that matter, are very imperfect tools for figuring out how different clusters formed. Indeed, they are very imperfect even for discovering individual ethnicity. An adoptee searching for information about ancestry who plots in the Balkans could indeed have Balkan ancestry, or could be a product of a British and Ashkenazi union. I know it can happen, because I used to share with someone with that mix who did indeed plot, there.
Absent ancient dna, the best tool we have is IBD analysis, and to the best of my recollection, the most IBD sharing between Ashkenazim/Sephardim and gentile European populations is with Greeks, and secondarily and in a more minor way, with Eastern Europeans.
Indeed, the offspring of a British-Ashkenazi union will usually plot in a genetic no man's land in between Bulgarians, Romanians, North Italians & Tuscans.
As you said, the only useful tool in that case is IBD analysis.