Our Messy Ancestry

Post date: Jul 26, 2012 9:44:33 PM

There's new genomic evidence, published today in Cell (subscription required*) and reviewed in the New York Times, about species from the genus Homo that coexisted in Africa with populations of what became modern humans. These species are genomically similar to Neanderthals, although a little bit different. There is evidence that these other Homo species were interbreeding with what are considered the ancestors of modern humans, about 20-80 thousand years ago. This adds to the growing pile of genomic evidence that indicates that there was a lot of interbreeding between human subspecies over the past several hundred thousand years, up until about 17 thousand years ago.

The Times tries to make a big deal out of some anthropologists claiming that the new genomic findings are overstated. First, I doubt that anthropologists as a whole disagree so strongly with this new genomic evidence. Second, I don't see the new data as being shocking, or terribly different from what we already knew about our salacious past. And finally, someone should remind the objecting archaeologists and paleoanthropologists that just because they can't find fossil evidence of a species being present in a particular place at a particular time doesn't mean that the species was definitely absent from that particular place at that particular time: absence of evidence is not evidence of absence.

Certainly, we still need discoveries and studies of macrofossils. But we live in an exciting time, when genomic data is giving us a more complete and interesting understanding of our history on this planet.

* I'm sorry that I can't give you access to this full article. If this bothers you, encourage more scientists to pursue open-source publication!