re: #3 CriticalDragon1177

Actually from what I understand Neanderthal genes did end up in sub Saharan African populations in prehistoric times, because human beings were still mating with each other all across the board. Still it is ironic, given the fact that humanity might not be where it is today, if we were “pure”

You’re saying “New Scientist” got it wrong? Interbreeding doesn’t always carry a small genetic contribution from “outside” into the fixed genome of a partially isolated population. It depends on whether the gene that is introduced confers some selective advantage. The probability that the gene will become fixed in its new population, despite having been introduced just a handful of times, is near zero if it confers only a small advantage, and is effectively zero if it is neutral.

We may reasonably speculate that the Neanderthal genes that did go to fixation in the outside-Africa population conferred some advantage that was local to outside-Africa, such as resistance to diseases found outside Africa, or resistance to cold. Or they were neutral, and got carried along for the ride by genes that did confer an advantage.

As to purity, it’s way overrated. Humans, and not just humans, are so “impure” as to incorporate in their genome fragments of virus DNA. DNA from vessels so far on the evolutionary tree from ourselves that it’s hard to find anything farther.

And we’re built to be attracted to exotic mates. The tall, dark, handsome stranger. The mysterious woman. Etc. Stock figures from literature are stock for a reason: outbreeding (within the species, and it seems, even a bit outside that fairly wide perimeter) pays.