What is the currently accepted explanation for the Sicilian/Ashkenazi genetic similarity?
Which is it?
a) Ashkenazis are primarily descended from southern Italian or Sicilian converts? This would suggest that Israelites, when expelled from Israel, first landed in Italy and then intermarried so much and converted so many people before moving north, and the descendants of these converted Italians became the ancestors of Ashkenazi Jews,
or
b) there is no direct admixture between the two groups, but Sicilians and Ashkenazis are of similar genetic components by chance (Greco-Roman, Levantine, NW European) and happen to come out similarly?
To me it would be highly coincidental and up to chance, to assume that two ethnicities that did not intermix with one another could develop nearly identical rates of admixture. Ashkenazi Jews on many DNA tests and admixture runs get their first match as Sicilian, and I've yet to see one that does not. But I notice that on different Gedmatch calculators, if both Ashkenazi and Cretan are reference samples, people from eastern Sicily and Calabria get "Cretan" as their first non-Sicilian match, and western Sicilians get "Ashkenazi".