[Jewbacca]

It’s a junk study.

What is more likely is Jewish people in Italy converted to Roman Catholicism, either in an attempt to blend in or by force (forced baptisms of Jewish children was a common practice, followed by stealing them and giving them to childles upper class families).

Leanardo DaVinci, for example, was maternally Jewish.
Chris Columbus, another.

[masadaman]

"Junk study" is a bit harsh as it was a study to find markers for inherited disease traits. But to the extent the study results are used politically instead of for science then it is worse than junk.

Columbus, based on several biographies, was from Genoa. And an often used shorthand, Genevoese, referring to Jewish Italians is common, yet I believe that there isn't any evidence that he was Jewish. Will Durant in his "Story of Philosophy" speculated on this as well suggesting that 1492's Voyage to the New World was not a search for riches but for a refuge for the Jews as the date coincided with the beginning of the Inquisition in Spain. Would appreciate references for Columbus and DaVinci as well.