Not to dismiss genes but it’s not an absolute. No group is racially pure. And DNA evolves over time. Thus greater and greater admixture . And even among the minority element of Jews that are genius level few could compete with someone like Einstein. It’s like a bell curve and that bell curve’s shape changes with time..
Ideology also plays a huge role too. Name me three great Jewish physicists from the middle ages. It’s only in the modern era you see great Jewish scientists in large numbers precisely because Jews started to either take their religion more metaphorically or dump it entirely This happened to Christians during the Renaissance and later Enlightenment when Jewish scientific achievements were still miniscule. If the ultra religious element in Israel took over Israel entirely and shut down your physics and math departments so you could study the Torah all day like they do you’d turn into a backwater.
One of Greece’s problems today is we are one of the most religious Christian countries in the world. And you can see the negative effects of that in our intellectual output. Ideology matters.