Columbus DEFINITELY WASN’T ITALIAN because Italy didn’t then exist.
However, his father, grandfather and great-grandfather were weavers in Genoa, seat of the Repubblica di Genova.
"...We have DNA from Christopher Columbus, very partial, but sufficient. We have DNA from Hernando Colón, his son," Lorente said in the documentary. "And both in the Y chromosome [male] and in the mitochondrial DNA [transmitted by the mother] of Hernando there are traits compatible with Jewish origin...."
By Jewish law, it doesn't count unless he had UNBROKEN Jewish matrilineality. If any of the women he was directly descended from were Gentile, Columbus could have been a "seed of Israel," in which case he would be considered ethnically BUT NOT RELIGIOUSLY Jewish, and only would have been considered religiously Jewish if he formally converted.
https://en.wikipedia.org/wiki/Matrilineality_in_Judaism