Genome-wide data from medieval German Jews. Preprint.

[A. Papadimitriou]

I think this clearly shows there was a Khazar-contribution. There's more on Eurogenes, but the levels of Siberian are far too high to be explained by Eastern European admixture (unless there was some secret medieval Finnic kingdom in Central Europe). Two groups of Jews, the Zarphatic (ie French Jews) and the Ashkenazic (ie Steppe Jews) merging. Explains why some Ashkenazim are so light too.

Why Khazar and not pre-Khazar?

[ihype02]

Target	Distance		Polish	Sephardic_Jew
Ashkenazi_Poland	0.01003676	•	16.6	83.4
Ashkenazi_Ukraine	0.01030672	•	18.8	81.2
Ashkenazi_Russia	0.01525090	•	19.4	80.6
Ashkenazi_Germany	0.01579246	•	10.2	89.8
Ashkenazi_Lithuania	0.01726847	•	17.8	82.2
Ashkenazi_Belarussia	0.01758130	•	18.8	81.2
Average	0.01437277	•	16.9	83.1

Pre Slavic Ashkenazi Jews seem to be pretty much like Sephardic Jews.

[Angela]

Given it's only about 500 years ago, the best test to use would be IBD analysis.