Sex with Other Early Species Might Have Been Secret of Homo sapiens Success
Just a few tens of thousands of years ago, Homo sapiens existed next to several close evolutionary cousins, including Neanderthals and Homo floresiensis. But shortly after our human species migrated out of Africa, we were left as the only hominin species on Earth.
What was the secret to our success? Did we out-compete the others for resources? Did we just flat-out kill them? Did we reproduce faster? All of those theories have some merit, but thanks to DNA analysis of ancient human and Neanderthal genomes, a new idea is emerging: We may have interbred our way to the top.
By analyzing how much of our genomes (nuclear and mitochondrial) we share with these other species, it appears that there was significant “genetic mixing”, if you know what I mean. Many of these hybrid gene mixes could have added new tools for our early immune system, leading to tougher, more survivable humans.
We still lack many details in this story, and lots of questions remain. But it’s pretty clear that human evolution does not follow a single line out of Africa. Instead, it’s a web that stretches first across Europe and then into Asia, mixing and branching along the way into the global population that today we see mixing in entirely new ways.
Check out the wonderfully detailed full story by Michael Hammer at Scientific American.