@LiberalLibrarian It's more complicated than that, isn't it? In biblical times they started out as half-siblings. 2000 years of diaspora has incorporated a lot of other DNA. Plus, it has been tradition that anyone wanting to convert to Judaism was welcomed. Descendants of these converts would not have the historic genetic markers.
@danielbsmith Not according to recent studies.
https://www.science.org/content/article/jews-and-arabs-share-recent-ancestry