Ancient skull a new window on human migrations, Denisovan meetings - Ars Technica

Like the Neanderthals, they are an early branch off the lineage that produced modern humans and later intermingled with modern humans.

At this time, there were distinct East Asian and East Eurasian (or Siberian) populations, with the latter being somewhat related to West Eurasians.

A 40,000-year-old skeleton from near Beijing is clearly closest to modern East Asians but is most closely related to a skeleton found in Belgium (!??!?).

A 45,000-year-old Siberian skeleton doesn't seem to have any modern relatives, while a 24,000-year-old individual from the same region identified the population that mixed with East Asians to produce the ancestors of Native Americans.

But two other Siberian skeletons from roughly the same time period don't show that affinity and just look generally Eurasian.

They first looked for sequences that matched human DNA to pull out all human-like sequences.

Most of the variations in the DNA matched those of modern humans, but there were a number of regions that matched Neanderthals and Denisovans.

The modern human portions most closely matched East Eurasian and Native American populations, which confirms the earlier results.

"The [newly described] Salkhit individual shares as many alleles with the Tianyuan [Beijing] individual as with the ~31,000-year- old Yana individuals from northeastern Siberia," the researchers write, "yet the Tianyuan and Yana individuals share fewer alleles with each other than with the Salkhit individual." Overall, the researchers conclude that, sometime after Western and Eastern Eurasian populations separated, there was some interbreeding between Eastern Eurasians and East Asians.

But of course, the newly described Siberian DNA has a remarkable similarity to the skeleton from Belgium, suggesting that at least some West Eurasian DNA was still being brought back into the lineage.

As far as Neanderthals go, the new Siberian skeleton is pretty typical of modern Asian populations, with about 1.7 percent of its DNA coming from Neanderthals.

And the Denisovan DNA that is present is more consistent with the amount seen in later East Asian skeletons.

The obvious conclusion from this is that modern humans intermingled with Denisovans on at least two distinct occasions.

That's something that had been indicated by other results, but modern East Asians have DNA from both of these events.

It was clearly Denisovan, with a slight possibility of a small fraction of modern human DNA.