I would imagine that at a genetic level, no one is a racial purebred. If all of us look back far enough, we will find that a thousand or so years ago, some conquering warrior "bred" with a local woman. A nobleman bred with a peasant girl. A master bred with a slave girl, etc, etc, etc.
I think if they’d done DNA testing in 1940....around ten percent of the accepted “German” society...would have failed the test because they had markers.
Some might argue we all link back to Noah or his progeny.
I noticed a few years ago that Einstein made the list of the top 50 Germans ever in a poll by a popular German magazine, though he was warned by his friend, the German consul in New York, while planning to his return to Germany in 1938, that if he showed up in Berlin they’d drag him through the streets by his hair.
Einstein was one of the 50 most prominent Germans ever, even though their grandparents would have considered him an Untermensch.