"Once upon a time, in a cave in the Altai Mountains of southern Siberia, different types of ancient peoples were having sex," I wrote last year in "The Cave Where It Happened: the Daughter of a Neanderthal Mom and a Denisovan Dad."
That long-ago admixture, plus other episodes, is why some of us have echoes of Neanderthal and Denisovan genomes in our DNA today. It's why some people learn from consumer genetic testing that 4% of their ancestors were Neanderthal. (Not the oft-claimed 3 or 4% of a genome, given that we share 98% of our genomes with chimpanzees.)
A new paper in Science Advances from the Baboon Genome Analysis Consortium provides a compelling possible view of our own prehistory, exploring genetic relationships among the six living species of genus Papio, the baboon. The animals maintain the traits that we say make them distinct species, differing in shape, size, and behavior, yet when members of different species meet, in geographical "hybrid zones," sometimes they indeed swap genes.
Have sex, that is.
To continue reading go to DNA Science, my weekly blog for Public Library of Science, where this post first appeared.