Modern humans co-existed and interbred not only with Neanderthals, but also with another species of archaic humans, the mysterious Denisovans. Research now describes how, while developing a new genome-analysis method for comparing whole genomes between modern human and Denisovan populations, researchers unexpectedly discovered two distinct episodes of Denisovan genetic intermixing, or admixing, between the two. This suggests a more diverse genetic history than previously thought between the Denisovans and modern humans.
What is known about Denisovan ancestry comes from a single set of archaic human fossils found in the Altai mountains in Siberia. That individual’s genome was published in 2010, and other researchers quickly identified segments of Denisovan ancestry in several modern-day populations, most significantly with individuals from Oceania but also in East and South Asians.
“The assumption is that admixing with Denisovans occurred fairly quickly after humans moved out of Africa, around 50,000 years ago, but we do not know where in terms of location,” Browning says. She theorizes that perhaps the ancestors of Oceanians admixed with a southern group of Denisovans while the ancestors of East Asians admixed with a northern group.
Going forward, the researchers plan on studying more Asian populations and others throughout the world, including Native Americans and Africans. “We want to look throughout the world to see if we can find evidence of interbreeding with other archaic humans,” says Browning. “There are signs that intermixing with archaic humans was occurring in Africa, but given the warmer climate no one has yet found African archaic human fossils with sufficient DNA for sequencing.” Paper. (public access) – Browning, SR, et al. Analysis of Human Sequence Data Reveals Two Pulses of Archaic Denisovan Admixture. Cell, 2018 DOI: 10.1016/j.cell.2018.02.031
A single set found in 2010? A lot hangs on that thread.
Also, what exactly does the term “interbred” mean? Does it mean that people who are not close relatives (not in a forbidden degree of consanguinity, to use an old term) get married? If not, what?
How do we know that the Denisovans are that different from other humans? Or the Neanderthals? What if the standards applied to them were applied to the acknowledged human population today?
See also: Researchers: Paleontologists are naming too many species
Nothing says “Darwin snob” like indifference to the mess that the entire concept of speciation is in