Archaic Hominin News

The flow of genes in multiple episodes between Neanderthals and modern humans is now better understood, and we have a new Denisovan genome from 200,000 years ago with better quality than any previous Denisovan genome. Via Razib:

Recurrent gene flow between Neanderthals and modern humans over the past 200,000 years:

Our understanding of admixture between humans and Neanderthals has changed dramatically over the past decade and a half. Once thought not to have occurred at all, there is now ample evidence for gene flow from Neanderthals to humans and vice versa. Li et al. used a new framework to model the increasingly complex dynamics of introgression between humans and Neanderthals and the ramifications for both populations. They identified regions of human ancestry in Neanderthals, estimated population sizes for Neanderthals were about 20% lower than previously thought, and proposed the possibility of two pulses of gene flow from humans to Neanderthals. This study comprehensively synthesizes our current knowledge of hominin admixture. —Corinne N. Simonti.

The most ancient human genome yet has been sequenced—and it’s a Denisovan’s. 24x, high quality, 200,000 years ago.

From the Denisovan link:

“I’m pleased to tell you about a new Denisovan genome from a 200,000-year-old male,” said [Stéphane] Peyrégne, a postdoc at the Max Planck Institute for Evolutionary Anthropology.

The genetic sequence he unveiled is the oldest high-quality human genome yet—80,000 years older than the previous record holder: a Neanderthal that lived about 120,000 years ago. The new results come after more than a decade of effort to find fossilized bones and a second genome of a Denisovan, the mysterious archaic human discovered through its DNA 14 years ago. That first Denisovan genome came from a girl’s pinkie finger bone dated between 60,000 to 80,000 years ago. The genomes of both Denisovans and the ancient Neanderthal all came from the same cold, fossil-rich site: Denisova Cave in the Altai Mountains of Siberia.

According to the analysis by Peyrégne and colleagues, the newly sequenced male comes from a distinct population of early Denisovans that interbred multiple times with a group of Neanderthals whose population had not been detected in DNA before. . . . 

Denisovans are primarily known from their DNA. Researchers have the genome of the girl, as well as bits of nuclear and mitochondrial DNA from fragmentary fossils—teeth, a toe bone—of seven additional individuals, all also from Denisova Cave. Scientists have also identified some Denisovan DNA in living humans, including in Papuans and Han Chinese people, acquired from past interbreeding. DNA in sediments showed that Denisovans were first in the cave 300,000 years ago, and later lived in a cave on the Tibetan Plateau. The scanty fossils reveal this archaic human had larger molars than did the Neanderthals and a robust lower face, known from a jawbone in China. . . . archaeologist Maxim Kozlikin of the Russian Academy of Sciences (RAS) found a molar in a deep layer dated to 200,000 years ago, Peyrégne reported in his talk. The RAS team sent the molar to Max Planck, where evolutionary geneticists extracted enough DNA to provide 24-fold coverage of the genome. . . .

the male Denisovan had inherited 5% of his genome from an ancient, previously unknown population of Neanderthals. The male, labeled Denisova 25, came from a separate population of Denisovans from the girl, known as Denisova 3, and from the other Denisovans in the cave. The girl’s DNA is more closely related to the Denisovan sequences in living modern humans, who got them from at least two Denisovan populations.

All this suggests the older male’s population was replaced in the cave by later Denisovans. . . . the male Denisovan’s ancestors interbred multiple times with Neanderthals. Denisovans were apparently replaced in the cave by Neanderthals for a period, based on the Neanderthal fossil dated to about 120,000 years ago. By about 60,000 years ago, though, the Denisovans had moved back in. The two groups may even have met in the cave—DNA from a bone fragment from a female who was more than 50,000 years old shows her mother was a Neanderthal and her father a Denisovan. Later, both DNA and fossils indicate modern humans occupied the cave and Denisovans and Neanderthals disappear. . . .  

Although Denisovans and Neanderthals apparently interbred repeatedly, their lineages are distinct: They diverged from a common ancestor at least 400,000 years ago. The ancestors of Neanderthals settled in Europe and the Middle East, whereas Denisovans headed farther east into Asia where they evolved separately, acquiring roughly 300,000 genetic changes that differentiate them from Neanderthals, according to the new genome. “Neanderthals and Denisovans remain in separate groups,” and mixed at the edges of their geographic ranges. . . . 

an audience member asked whether the male’s genome also had DNA from an even older, unidentified type of human–perhaps Homo erectus—whose DNA has been spotted in the Denisovan girl’s genome. “If there is any Denisova superarchaic ancestry, it’s also present in this genome,” Peyrégne responded. “[That DNA] is shared between Denisova 3 and Denisova 25.”

See also speculations on the Yeti myth is an oral history recollection of Denisovans in Tibet at the Old European Culture Blog, and John Hawks post about large brained archaic hominin Julurens in China, who could be cousins of Neanderthals and Denisovans.