[Cronos]

And, of course, as noted above, as many as 1/4 of today’s Spaniards have Jewish blood, so yes it is a near certainty that many of Columbus’ crew members were heavily or party of Jewish ancestry

[ChicagoHebrew]

And, of course, as noted above, as many as 1/4 of today’s Spaniards have Jewish blood.

Well, it's been about 20 generations since the Expulsion. So I'd guess that nearly every Spaniard has some Jewish blood. Franco conveyed as much to the Nazis when the Nazis asked that he institute the Nuremberg laws.

But some of the studies linking Jews to present-day Spaniards are just bad science. One study, for instance, focused on Y-chromosomes and assumed that every Spaniard with certain Y-chromosomes are descended from Jews. But, in actuality, those particular chromosomes aren't particularly Jewish, and could just as easily be traced to other Middle Eastern groups who formed part of the ancestrial Spanish population, such as the Phoenicians/Carthaginians.