Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia

Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia
Three-rooted lower second molar of Xiahe Denisovan individual. Credit: The Max Planck Institute

An analysis of a 160,000-year-old archaic human molar fossil discovered in China offers the first morphological evidence of interbreeding between archaic humans and Homo sapiens in Asia.

The study, which appears in the journal Proceedings of the National Academy of Sciences, centers on a three-rooted lower —a rare trait primarily found in modern Asians—that was previously thought to have evolved after H. sapiens dispersed from Africa.

The new research points to a different evolutionary path.

"The trait's presence in the fossil suggests both that it is older than previously understood and that some modern Asian groups obtained the trait through interbreeding with a sister group of Neanderthals, the Densiovans," explains Shara Bailey, a professor of anthropology at New York University and the paper's lead author.

In a previous study, published in Nature, Bailey and her colleagues concluded that the Denisovans occupied the Tibetan Plateau long before Homo sapiens arrived in the region.

That work, along with the new PNAS analysis, focused on a hominin lower mandible found on the Tibetan Plateau in Baishiya Karst Cave in Xiahe, China in 1980.

Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia
The three-rooted lower molar anomaly in a recent Asian individual. Left: tooth sockets showing position of accessory root; right: three-rooted lower first molar tooth. Credit: Christine Lee

The PNAS study, which also included NYU anthropologist Susan Antón and Jean-Jacques Hublin, director of the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology, centered on the molar, with the aim of understanding the relationship between archaic humans who occupied Asia more than 160,000 years ago and modern Asians.

"In Asia, there have long been claims for continuity between archaic and modern humans because of some shared traits," observes Bailey. "But many of those traits are primitive or are not unique to Asians. However, the three-rooted lower molar trait is unique to Asian groups. Its presence in a 160,000-year-old archaic in Asia strongly suggests the trait was transferred to H. sapiens in the region through interbreeding with archaic humans in Asia."


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First hominins on the Tibetan Plateau were Denisovans

More information: Shara E. Bailey el al., "Rare dental trait provides morphological evidence of archaic introgression in Asian fossil record," PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1907557116
Citation: Ancient molar points to interbreeding between archaic humans and Homo sapiens in Asia (2019, July 8) retrieved 22 July 2019 from https://phys.org/news/2019-07-ancient-molar-interbreeding-archaic-humans.html
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Jul 09, 2019
Can someone explain how ''evolution'' worked when several, or perhaps more, humanoid species existed at the same time? Evolution isn't inbreeding is it? If Denisovans, Neanderthals, Archaic Humans, and Asians and others interbred, where does the ''evolution'' come in.

Jul 09, 2019
Can someone explain how ''evolution'' worked when several, or perhaps more, humanoid species existed at the same time? Evolution isn't inbreeding is it? If Denisovans, Neanderthals, Archaic Humans, and Asians and others interbred, where does the ''evolution'' come in.


Evolution is simply 2 things: 1) Inheritable variation over generations 2) "Natural selection" or (to dump the anthropomorphic metaphor) the variations that do not contribute to the next generation are filtered out by the difficulties of surviving and reproducing.

The story here is that these variations of humans had already been produced by these 2 steps from earlier anthropoid apes, either the Australopithecines ("Lucy" being an example of one variety/species) or something like them.* Unfortunately, the story since then seems to be dominated by step 2.

* Believe it or don't.

Jul 10, 2019
Thank you but that doesn't seem to answer my question. What I am asking is if the Neanderthals, humanoids evolved from, let'e say Lucy, the example you gave, did the Denisovans also ''evolve'' from her, or was there another yet unfound ''Lucy'', possibly a descendant of Lucy or possibly her sister ? If Neanderthals and Denisovans were contemporaries, they certainly couldn't have evolved from each other. That is my point. I am not denying evolution I'm just fascinated with this information that is constantly being discovered and which seems to suggest that we didn't evolve in the same way that the birds that Darwin studied that were the same in many ways but had different beaks because of the foods available.

Jul 10, 2019
... I am not denying evolution I'm just fascinated with this information that is constantly being discovered and which seems to suggest that we didn't evolve in the same way that the birds that Darwin studied that were the same in many ways but had different beaks because of the foods available.


Actually, the story is just the same for Darwin's "finches" and humans. Neanderthals, Denisovans, and H. sapiens sapiens are all supposed to be variations of an ancestral population similar to Australopithecines, and the minor variations (which didn't prevent them from interbreeding) are comparable to the beaks, which continue to vary on each generation of birds, which can also interbreed, and are all descendants of one or a few "Lucy" birds.

Jul 15, 2019
joker, you are confusing the words used to classify our ancestral hominids

this is due to our history of all the pseudo-science, politics & religious beliefs in ordained superiority over anyone who lacks modern weaponry

the pseudo-science of eugenics
just consider the recent mass deaths among modern race-horses due to the inherent stupidity of the Stud Book
after all, inbreeding worked so well for the Hapsburg, Bourbon dynasties & now the Saudis?
just check out their present World-dominating empires
ohh, just wait for it!

joker, my advice is ignore the irrelevant categories beloved of the OCD science-bureaucrats-in-training

& follow the newest DNA evidence which clearly defines whose ancestors were actually to blame for raping your lineage
NONE OF US can escape the inexorable humiliation of History's judgement

we are Human, we screw up screwing anyone we can get drunk enough to tolerate us for an hour or so in a dark cave

it defines us as a biological species

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