Neanderthals and modern humans diverged at least 800,000 years ago

Neanderthals and modern humans diverged at least 800,000 years ago
Dental morphology. Credit: Aida Gómez-Robles

Neanderthals and modern humans diverged at least 800,000 years ago, substantially earlier than indicated by most DNA-based estimates, according to new research by a UCL academic.

The research, published in Science Advances, analysed dental evolutionary rates across different , focusing on early Neanderthals. It shows that the of hominins from Sima de los Huesos, Spain—ancestors of the Neanderthals—diverged from the modern lineage earlier than previously assumed.

Sima de los Huesos is a cave site in Atapuerca Mountains, Spain, where archaeologists have recovered fossils of almost 30 people. Previous studies date the site to around 430,000 years ago (Middle Pleistocene), making it one of the oldest and largest collections of human remains discovered to date.

Dr. Aida Gomez-Robles (UCL Anthropology), said: "Any divergence time between Neanderthals and younger than 800,000 years ago would have entailed an unexpectedly fast dental evolution in the early Neanderthals from Sima de los Huesos."

"There are different factors that could potentially explain these results, including strong selection to change the teeth of these hominins or their isolation from other Neanderthals found in mainland Europe. However, the simplest explanation is that the divergence between Neanderthals and modern humans was older than 800,000 years. This would make the evolutionary rates of the early Neanderthals from Sima de los Huesos roughly comparable to those found in other species."

Modern humans share a common ancestor with Neanderthals, the extinct species that were our closest prehistoric relatives. However, the details on when and how they diverged are a matter of intense debate within the anthropological community.

Neanderthals and modern humans diverged at least 800,000 years ago
Hominin teeth. Credit: Aida Gómez-Robles

Ancient DNA analyses have generally indicated that both lineages diverged around 300,000 to 500,000 years ago, which has strongly influenced the interpretation of the hominin fossil record.

This divergence time, however, is not compatible with the anatomical and genetic Neanderthal similarities observed in the hominins from Sima de los Huesos. The Sima fossils are considered likely Neanderthal ancestors based on both anatomical features and DNA analysis.

Dr. Gomez-Robles said: "Sima de los Huesos hominins are characterised by very small posterior teeth (premolars and molars) that show multiple similarities with classic Neanderthals. It is likely that the small and Neanderthal-looking teeth of these hominins evolved from the larger and more primitive teeth present in the last of Neanderthals and modern humans."

Dental shape has evolved at very similar rates across all hominin species, including those with very expanded and very reduced teeth. This new study examined the time at which Neanderthals and modern humans should have diverged to make the evolutionary rate of the early Neanderthals from Sima de los Huesos similar to those observed in other hominins.

The research used quantitative data to measure the evolution of dental shape across hominin species assuming different divergent times between Neanderthals and modern humans, and accounting for the uncertainty about the evolutionary relationships between different hominin species.

"The Sima people's teeth are very different from those that we would expect to find in their last common ancestral species with modern humans, suggesting that they evolved separately over a long period of time to develop such stark differences."

The study has significant implications for the identification of Homo sapiens last common ancestral species with Neanderthals, as it allows ruling out all the groups postdating 800,000 year ago.


Explore further

Teeth of Homo antecessor shed light on trends in Pleistocene hominin dental evolution

More information: A. Gómez-Robles at University College London in London, UK el al., "Dental evolutionary rates and its implications for the Neanderthal–modern human divergence," Science Advances (2019). advances.sciencemag.org/content/5/5/eaaw1268
Journal information: Science Advances

Citation: Neanderthals and modern humans diverged at least 800,000 years ago (2019, May 15) retrieved 17 July 2019 from https://phys.org/news/2019-05-neanderthals-modern-humans-diverged-years.html
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May 15, 2019
and the taxonomy folks placed the divergence at ~250,000 ya

May 15, 2019
and the taxonomy folks placed the divergence at ~250,000 ya


I doubt that. The first modern human remains date from around that time. Previous estimates I'd seen were ~ 400-500 ka.

May 15, 2019
The title is misleading - the study makes no absolute claim at 800ka BP. It says based on observations of evolutionary rates of teeth, to account for the differences between this group of Neanderthals and modern humans, a divergence of this line earlier than 800ka BP would mean Neanderthal would have experienced accelerated changes vs what might be expected.

Considering that divergence has been claimed anywhere from 300ka BP up to 650ka BP, I think that's entirely fair to say, based on this data, we can safely say a divergence at centered ~800ka BP likely occurred.

It doesn't mean 800Ka BP minimum and absolutely Neanderthal and Homo Sapiens separated. If anything, it means that the relationship between Neanderthal emergence vs modern human emergence, and the known interaction between our species, including that interaction which occurred much much closer to today, was even more complex than the complexity we already have before us.

May 15, 2019
I would like to know if Neanderthalensis sported a baculum. If they did have a baculum, then they would have been closer to the apes such as gorillas, bonobos and chimpanzees than they were to modern humans even though both existed at around the same time.
Doubtful that it is possible to know this from a few teeth. But if they have found whole male skeletons, that would be the best and only place to find the baculum. If not found, then there would be a good possibility that Neanderthals were closer to their human counterparts than to the apes after all.

May 15, 2019
Well, first unresolved problem with all the scientific research into our ancestry is? First we all have to agree on what we mean by terns such as "Human", "Pre-Human". "Ancestry",

An amusing observation is too realize that we monkey's cannot even agree to not disagree about whateverinthehell it is
we are pretending to be agreeably consistently disputing!

In my opinion, Hominid is those ancestors sharing DNA.
& as sillyeggfeads auntie would say " Doesn't matter if his cousins are all born with a prehensile tail!"

May 15, 2019

https://www.ncbi....3263034/

jonesy has expressed his belief that he is descended from apes. The above link might give jonesy a better understanding. And rrwillisj still makes no sense.

May 16, 2019
Neanderthals descended from Homo erectus in Europe. Modern humans descended from Homo erectus in Africa.

So, I'm unclear on the concept of Neanderthals and modern humans 'diverging'

May 16, 2019
Ken, in the end (cough) it always comes back to the sex.
Who is doing What! to Whom?

Just for the fun of it. In addition to the Neanderthals. Figure out where the Denisovan fit into this happy family with our ancestral Homo Anthropophagus ancestors.

May 16, 2019
Denisovans are either descended from Homo erectus in Asia, or they are a relic Homo erectus that persisted in Siberia long after they had gone extinct in south eastern Asia. Their DNA is much further removed from that of modern humans than Neanderthal DNA, so the relic H. erectus hypothesis seems more likely.

May 16, 2019
Well, I guess that description "Homo Erectus" was well deserved!

May 16, 2019
I don't doubt the data (n=30+ just from the Sima de los Huesos sample) or the analysis, but dating using just one phenotypic trait is iffy.

"Paleoanthropologist Rick Potts, director of the Smithsonian's Human Origins Program, says that while Gómez-Robles raises some plausible ideas, he's far from convinced that rates of dental evolution are as standard or predictable as the paper suggests. "She's bitten off an interesting topic here, but I just don't see the argument that dental rates of evolution are absolutely known to the point where we can then say that for certain the Neanderthal-modern human divergence must have been earlier than 800,000 years ago," Potts says. "A variety of molecular genetic studies suggest it's more recent."

- tbctd -

May 16, 2019
- ctd -

"Potts also points out several possible causes of misinterpretation, including a variable called "generation time" that could greatly impact the ... Scientists do have evidence that the speed of tooth development changed over evolutionary time. ... Hybridization between different species, which appears to have been rampant during the era, is another possible complication."
[ https://www.smith...pIKVl.99 ]

- tbctd -

May 16, 2019
- ctd -

Nitpick: "Ancient DNA analyses have generally indicated that both lineages diverged around 300,000 to 500,000 years ago, ..." Most recent analyses converge on 600,000 years, which the paper notes and uses; a recent example not referenced in the paper gets a 603 kyrs age within the 95 % confidence interval 496 to 797 kyrs: https://genomebio...9-1684-5 . There isn't enough tension between the data sets to suggest a dating method problem here.

I more or less completely agree with Omikron here. The paper itself suggests that the discrepancies are due to an incomplete fossil record (where have we heard that plaint before?), simply giving the Sima de los Huesos sample too much statistical weight despite being adamant on uniform rates (but having large standard deviation on them). It is pretty much agreeing with Potts right there.

May 16, 2019
rjwills; "Well, I guess that description "Homo Erectus" was well deserved!"
Ah, the lengths some will go to in order to get a rise out of those easily excited by suggestive double entendre...

May 16, 2019
well, TB, got your attention, did I not?

i prefer to think of myself as being satirical, butt perhaps i should spell it satyrical?
Not to cause a panic?
I better pipe myself off this loveboat.

May 20, 2019
Hmm, yes, why isn't the big news "surprisingly high rate of tooth evolution discovered"? And I have reports of fossils identified as modern human going back as far as almost 300 thousand years, with some teeth dated 400 thousand. Even that would be only half of this age of divergence. On the other hand, we all know there is evidence for interbreeding more recently than 100 thousand years ago. Can we agree there's a lot we don't know, and maybe we think we know more than we really do?

May 21, 2019
Hmm, yes, why isn't the big news "surprisingly high rate of tooth evolution discovered"? And I have reports of fossils identified as modern human going back as far as almost 300 thousand years, with some teeth dated 400 thousand. Even that would be only half of this age of divergence. On the other hand, we all know there is evidence for interbreeding more recently than 100 thousand years ago.


FWIW the whole genome paper I linked seem to show that in a comprehensive, statistically "superior" model. (Developed by an ingenious method of using approximate Bayesian computation as a template for machine learning.) I.e. the shadow African lineage they confirm split from modern humans about the same time Neanderthals and Denisovans split in Eurasia, and consistent with earlier genome+fossil data you mention.

Also, lots of introgressions with gene flow sizes compatible with Pääbo et al latest paper on Neanderthals+Africans. (Though the latter did not account for the African ghost.)

May 21, 2019
I would not say that we *know* this, but the increased gene flow seen in the introgressions are repeatable (and of course Pääbo et al are rock solid work). The African ghost has been seen in earlier work repeatedly.

And so has the Eurasian ghost I did not mention above, but which the paper see a remarkably late date for its gene flow into a Denisovan lineage and has labeled "Erectus" in the Supplements. Because, who else could it be!? The cross breeding occurred 1-2 million years since common split, which if correct confirms that other half as young human cross breeding were not too difficult.

Speaking of who else, I just checked and Naledi @ 250 kyrs ago is a possible ID for belonging to the African ghost lineage(s) [ https://en.wikipe...o_naledi ]. But Africa is the proverbial "home of splits", so who knows...

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