Oldest Evidence of Siberian Crossing of Native Americans

UPI has a story about evidence from around Lake Baikal that links populations of Siberia to the earliest groups who came over from Siberia to the New World.  Brooks Hays writes:

New genomic analysis of ancient remains in Siberia -- detailed this week in the journal Cell -- have offered scientists fresh insights into the movements of human populations across Eurasia and into the Americas at the end of the Stone Age.

“Previous studies observed the genetic differences between individuals from different time periods, but didn't investigate the differences by dating the admixture events,” lead study author He Yu, postdoctoral researcher at the Max Planck Institute for the Science of Human History in Germany, told UPI in an email. “Our study reports a 14,000-year-old individual, which actually fills in a large blank of ancient genomes in this region, between 23,000 and approximately 8,000 years ago.”

By using the DNA of a tooth from the 14 ky old individual, Yu and his team have established links to the earliest Native Americans.

“The deep connection observed in this study is sharing of the same admixed ancestry between Upper Paleolithic Siberian and First Americans," Yu said. "We are not suggesting interbreeding between Native American and Siberian, or any back flow of Native American ancestry into Siberia. But we are suggesting that, the First American ancestry was formed in Siberia and also existed there, in a large range of time and space, so we can detect it in ancient Siberian individuals.”

There have always been conflicting theories about how and when the migrations to the New World occurred and there has always been evidence for movements from the Lena River, in Siberia and the northern Amur river in northern China.

Interestingly, they also found genetic evidence of the plague in some of the Bronze age populations from the area, which they hypothesized came from Europe, indicating that there was considerable movement between these populations.

Neandertal/Denisovan Ancestors Interbred With Unknown Hominin

As if the tangle of early archaic Homo sapiens relationships couldn't get any more confusing, evidence has now surfaced that the ancestors of both the Neandertals and Denisovans interbred with a hominin only known from its DNA signature.  From the University of Utah, through Science Daily:

For three years, anthropologist Alan Rogers has attempted to solve an evolutionary puzzle. His research untangles millions of years of human evolution by analyzing DNA strands from ancient human species known as hominins. Like many evolutionary geneticists, Rogers compares hominin genomes looking for genetic patterns such as mutations and shared genes. He develops statistical methods that infer the history of ancient human populations.

According to the article, Rogers performed a study that argued that Neandertals and Denisovans separated earlier than has previously been suggested but that his evidence for this was thin.

The new study has solved that puzzle and in doing so, it has documented the earliest known interbreeding event between ancient human populations -- a group known as the "super-archaics" in Eurasia interbred with a Neanderthal-Denisovan ancestor about 700,000 years ago. The event was between two populations that were more distantly related than any other recorded. The authors also proposed a revised timeline for human migration out of Africa and into Eurasia. The method for analyzing ancient DNA provides a new way to look farther back into the human lineage than ever before.

"We've never known about this episode of interbreeding and we've never been able to estimate the size of the super-archaic population," said Rogers, lead author of the study. "We're just shedding light on an interval on human evolutionary history that was previously completely dark."

According the Rogers, the DNA evidence puts the final nail in the coffin of the complete Out-of-Africa replacement model of modern human origins:

The researchers also proposed there were three waves of human migration into Eurasia. The first was two million years ago when the super-archaics migrated into Eurasia and expanded into a large population. Then 700,000 years ago, Neanderthal-Denisovan ancestors migrated into Eurasia and quickly interbred with the descendants of the super-archaics. Finally, modern humans expanded to Eurasia 50,000 years ago where we know they interbred with other ancient humans, including with the Neanderthals.

This was likely something like Homo antecessor.  As is also true with the Chinese evidence, this evidence suggests that throughout human evolutionary history, there has never/rarely been a time when these groups of archaic and early modern Homo sapiens could not/did not interbreed. As J. Lawrence Angel once said “When two groups of people meet, they may fight, but they will always mate.”

The Science Advances article is open access. 

http://dx.doi.org/10.1126/sciadv.aay5483

The Ghost of an Unknown Hominin

Science Alert has a story about the Ghost of an Unknown Hominin in Africa.  Carly Cassella writes:

The gene pool of modern West Africans contains the 'ghost' of a mysterious hominin, unlike any we've detected so far. Similar to how humans and Neanderthals once mated, new research suggests this ancient long-lost species may have once mingled with our ancestors on the African continent.

Using whole-genome data from present-day West Africans, scientists have found a small portion of genetic material that appears to come from this mysterious lineage, which is thought to have split off from the human family tree even before Neanderthals.

It is not clear to me that these necessarily represent different species. This may reflect an inter-related group of populations from a very genetically diverse population. As my advisor Fred Smith once upon a time said: “If two species interbreed on a regular basis, is it reasonable to call them different species?”

BTW, the  “Unrelated” skull in the page is the Kabwe skull from What was once Rhodesia, discovered in 1925, 400 feet down, in a mine.

BBC: How Did the Last Neanderthals Live

The BBC has a post on some archaeological discoveries that have illuminated how the Neandertals lived.  Melissa Hogenboom writes:

For the most part, Neanderthals were a resilient group. They existed for about 200,000 years longer than we modern humans (Homo sapiens) have been alive. Evidence of their existence vanishes around 28,000 years ago – giving us an estimate for when they may, finally, have died off.

Fossil evidence shows that, towards the end, the final few were clinging onto survival in places like Gibraltar. Findings from this British overseas territory, located at the southern tip of the Iberian peninsula, are helping us to understand more about what these last living Neanderthals were really like. And new insights reveal that they were much more like us than we once believed.

It always seems to strike these writers as odd that Neandertals were capable of culture roughly equivalent to our own.  The last group of Neandertals lived at a time that was much harsher, climate-wise, than today, with the tundra line being equivalent in latitude, to Vienna.

The original Gibraltar skull was discovered in 1848 (eight years before the type specimen was discovered in the Neander Valley, in Germany).  Clive Finlayson, the Director of the Gibraltar Museum has been part of a team that has been excavating the set of caves there and four caves have been identified.

“It was in some way Neanderthal city,” he says. “This was the place with the highest concentration of Neanderthals anywhere in Europe.” It’s not known if this might amount to only dozens of people, or a few families, since genetic evidence also suggests that Neanderthals lived in “many small subpopulations.”

There is still considerable mystery surrounding just why the Neandertals faded out. The best theory going at the moment is gene swamping. Given that the Neandertal and early modern human genomes were both probably pretty stable, Neandertal/modern human mating could very well have resulted in hybrid depression. Eventually, the Neandertal genes, facing negative selection, dropped out of the genome.

EarthSky: Twenty years of discoveries changing story of human evolution

EarthSky has an interesting article that summarizes twenty years of human evolution discoveries.  They write:

Perspectives on our own species have also changed. Archaeologists previously thought Homo sapiens evolved in Africa around 200,000 years ago, but the story has become more complicated. Fossils discovered in Morocco have pushed that date back to 300,000 years ago, consistent with ancient DNA evidence. This raises doubts that our species emerged in any single place.

This century has also brought unexpected discoveries from Europe and Asia. From enigmatic “hobbits” on the Indonesian island of Flores to the Denisovans in Siberia, our ancestors may have encountered a variety of other hominins when they spread out of Africa. Just this year, researchers reported a new species from the Philippines.

All of these discoveries point to the idea that there was considerable population mixing throughout the Middle to Late Pleistocene not just in Africa but throughout the Old World. We know that it took place in China around 120,000 years ago by the evidence from Linjing.  These particular hominins have characteristics found in modern humans, Neandertals and Homo erectus.

Interestingly, the idea that our species did not originate in any single place was an idea pursued by Rachel Caspari almost two decades ago, at a paper given at one of the American Association of Physical Anthropologists conventions.  At the time, it was still thought that the “Out of Africa” replacement model was still the best explanation for modern human origins.We now know that it is not.

Denisovans More Closely Related to Modern Humans than Neandertals

Science Daily has a post relating recent research on the genetic studies involving the Denisovan material from Siberia.  The research, done by CNRS in France has this to report:

Now a team of scientists from the Institut Jacques Monod (CNRS / Université de Paris) has measured and photographed another fragment found in Denisova Cave. Genomic analysis reveals it is the missing piece of the same phalanx whose proximal fragment enabled initial sequencing of the Denisovan genome.

Together with colleagues from the PACEA laboratory (CNRS / University of Bordeaux / French Ministry of Culture) and the University of Toronto (Canada), the scientists compared the new fragment to the phalanges of Neanderthals and anatomically modern humans. Their analysis indicates it is very close to the latter, and less like the former..

This research suggests that there was considerable population mixing and genetic variability in this population, given the news that came out last year detailing the finding of a child skeleton that was, as nearly as the researchers could tell, the offspring of a Neandertal and a modern human.This just continues to solidify the idea that these groups interbred routinely throughout the late Pleistocene. 

More Information About the Denisovans

Discover Magazine has an article on new finds at Denisova and their context in early modern human evolution.  Bridget Alex writes:

Nestled in foothills of Russia’s Altai Mountains, Denisova Cave has been a research mecca since 2010, when fossil DNA from the site revealed a previously unknown human lineage, now called the Denisovans. Scientists have been working hard to reconstruct the cave’s history, through ongoing excavations as well as new analyses of materials recovered years ago.

First, what everyone wants to know: Yes, they found more human remains. In addition to the four Denisovan specimens (one pinky finger, two adult molars and a baby tooth), the cave has yielded 12 fossils from ancient humans, including teeth, toes, fingers and unclassifiable fragments.

Based on their genomes, proteins and physical appearance, the collection contains four Denisovans, three Neanderthals and one hybrid cross between the two human types. Excavators have also found four more fossils that belong to the Homo genus, but haven’t yet been assigned to a particular human species. Additional DNA sequences, recovered directly from the dirt, suggest the presence of even more individuals.

As reported last year, Denisova 11 has been determined to be the offspring between a Neandertal mother and Denisovan father. As with other finds in Asia, we are finding that there appears to have been considerable population mixing over the course of at least 100 thousand years. Although the article indicates that the Neandertals were “sandwiched” in between two modern human occupations, that is difficult to square with any hybridization model. I suspect that the habitation patterns were more complex.

Chris Stringer: Meet the Relatives

Chris Stringer has a post in the Financial Times titled Meet the Relatives.  It is sort of a whirlwind tour through the evolution of the genus Homo.    He writes:

The discoveries of Homo floresiensis, Homo luzonensis, Denisovans and Homo naledi in the past 15 years remind us that the fossil record of humans is still very patchy — stone tools are scattered across much of Africa as a witness to widespread human occupation, yet fossil evidence has been recovered from less than 10 per cent of that continent’s area.

The percentage coverage for Asia is hardly any better: there is, for example, currently only one significant human fossil from the whole of the Indian subcontinent. The discoveries of the past few years underline just how much evolutionary history remains unknown, with other extinct lineages no doubt still to be revealed.

Many of the new finds challenge how we classify fossils in relation to Homo sapiens today. I continue to call the Neanderthals a different species from us, based on their distinctive skeletons and skulls; others feel that the recent evidence of interbreeding and increasing evidence of sophisticated behaviour mean that we should merge them, and the Denisovans, into our species.

I think that the discovery of the Xuchang hominins indicates that there has been considerable population mixing for several hundred thousand years.  As I wrote at the time:

These two Chinese skulls stand at the crossroads of these population movements. While showing clear Neandertal characteristics, they also express modern traits, possibly reflecting mixing with the late, modern human arrivals represented by the recent modern human finds at Daoxian. Yet they also express a clear link to ancient East Asian populations. The implications of these skulls are stark: there has been widespread population mixing and regional continuity in Europe and Asia for at least 400 thousand years. Not only did the Neandertals feel enough cultural kinship to mate and have children with these East Asian people, the early modern humans coming out of Africa did, as well. As Chris Davis of China Daily News put it: “One big happy family.”

Whether this represents such behavior at the peripheries of different species or that of one polytypic species is, as yet, unclear.  It is very clear that our understanding of how these populations interacted is rudimentary, at best. 

Earliest Art Made By Humans?

Artnet News has a post on a discovery in Henan Province, China that purports to be the oldest indications of consciously-created art.  From Sarah Gascone:

Abstract patterns carved on bone fragments discovered in China could be the oldest art ever made, dating back to between 105,000 and 125,000 years ago.

The marks on two bones were found at a site in Henan Province thought to be populated by Denisovans, an extinct species or subspecies of ancient humans, according to a new study in the Cambridge University Press journal Antiquity. The markings on the weathered rib bones contain traces of ochre on one specimen, the earliest evidence of pigment’s use for decorative purposes.

The newly discovered artworks pre-date even the 73,000-year-old markings—thought by some to be abstract drawings—found last year on a rock excavated from a South African cave, and previously thought to be the earliest-known example of human artistic activity.

Here is an image of the markings:

Photo Credit: Francesco d’Errico and Luc Doyon.

There seems to be a persistent thought that people of this age simply could not make art of this kind. I think it more stems from the fact that this kind of representation rarely survives in the fossil record. We know that as far back as 300k, there was division of labor and that there was quite a bit of population mixing this far back.  There is also a record of Neandertal cave paintings at 65k.  It is nice to find this kind of artistic expression but it ought not to surprise us. 

New Species of Hominin Found in Phillipines

From a story in UPI:

At the completion of excavations on the island of Luzon, scientists had unearthed several teeth, part of a thigh bone, and a few hand and foot bones. The fossils comprise the "the earliest direct evidence of a human presence in the Philippines," according to the latest study.

The fossilized bones, dated to between 67,000 and 50,000 years ago, feature a mix of anatomical characteristics, some that recall more primitive hominins and others similar to those of more modern human species.

Callao Cave is toward the northern tip of Luzon. The corresponding article from Nature seems to indicate that the fossil remains from this cave are “all over the map.”  The premolars indicate size and shape affinities to later Homo, while some of the characteristics are australopithecine (!).  This is also true of the hand elements. 

Although we have found human fossil remains in East Asia for some time (1896 on), there are large gaps in our knowledge, especially from the first appearance of Homo erectus to the advent of modern humans.  These fossils, while giving us more  information than we had, muddy the waters a bit.  Once upon a time, Grover Kranz (RIP) tried to convince me that australopithecines could be found in East Asia, but his evidence was based on a badly crushed occipital bone. 

It is clear from the presence of H. floresiensis and the current evidence that primitive traits were being retained in some groups but, as the authors point out, we need quite a bit more fossil material to make any definitive assessments. 

Genetic Data Suggests That Early Modern Humans Migrated From South to East Africa

Science Daily is running a story that supports the idea that modern humans migrated from South to East Africa before exiting the continent.  Up until recently, all of the evidence seemed to suggest that South Africa, while having evidence of modern humans at Klasies Rivers Mouth, Border Cave and other sites, did not contribute to the migration out of Africa.  That has changed.

The Huddersfield-Minho team of geneticists, led by Professor Martin Richards at Huddersfield and Dr Pedro Soares in Braga, along with the eminent Cambridge archaeologist Professor Sir Paul Mellars, have studied the maternally-inherited mitochondrial DNA from Africans in unprecedented detail, and have identified a clear signal of a small-scale migration from South Africa to East Africa that took place at just that time, around 65,000 years ago. The signal is only evident today in the mitochondrial DNA. In the rest of the genome, it seems to have been eroded away to nothing by recombination -- the reshuffling of chromosomal genes between parents every generation, which doesn't affect the mitochondrial DNA -- in the intervening millennia.

Before going further, it is worth noting that purveyors of the mtDNA evidence have been burned before by incorrectly using the programs to input the information. Originally, those results supported a hard-line Out-of-africa model of modern human origins (Stringer and Andrews 1988), a model we now know is incorrect. Onward.The paper is available through Scientific Reports, which is open-access.  What is missing from this hypothesis is good human fossil material from South Africa which is between 160 and 200 ky.  The most current remains we have are around 120k.  More work needs to be done on this.

More Information From Denisova

Nature News is reporting about some more evidence from Denisova, following up on the bombshell news last year that bones discovered there belonged to a person (who they named “Denny”) who's father was a Denisovan and mother a Neandertal. From the story:

In the years that followed the discovery of Denisovans, scientists used DNA sequencing to attribute a few molar teeth from the cave to the same group4. They have also found other remains that harboured Neanderthal DNA. The analysis of Denny fills in some important details about the two groups. “We knew that Denisovans and Neanderthals had been there. We just didn’t think they interacted this intimately,” says [Svante] Pääbo. “It was so amazing to find direct proof — to find these people in the act, almost, of mixing.”

Denny’s discovery has also convinced Pääbo and other scientists that the remains of similar individuals, with recent ancestry from two groups of hominin, will be found — perhaps also in Denisova Cave. Researchers who analysed Denny’s genome found signs that the chromosome set that was contributed by her father, although clearly Denisovan, harboured some Neanderthal ancestry, which hints at earlier encounters between the groups2. “We should be able to pick up these individuals,” says [Katerina] Douka.

The Denisova cave appears to have been occupied for several hundred thousand years, being originally settled by either Denisovans or Neandertals, no one is sure which. Subsequent to this, it is unclear how much interbreeding actually occurred. 

“It’s still a head scratcher,” adds Tom Higham, an archaeological scientist at the University of Oxford, UK, who works with Douka and Brown. “It’s either an incredible piece of luck, or interbreeding happens so frequently that we might expect to find these types of occurrence in the archaeological record.”

One thing becomes increasingly clear with each new discovery, however: the complete replacement model of modern human origins, as espoused by Stringer and Andrews, is dead.

Neandertal Teeth 450Ky Old Found in Italy

The Smithsonian is reporting that excavations in Italy have uncovered teeth dated to 450 thousand years ago that have Neandertal characteristics.

A fossil tooth study published today in the journal PLOS ONE analyzes some of the oldest human remains ever found on the Italian Peninsula. The teeth, which are some 450,000 years old, have some telltale features of the Neanderthal lineage of ancient humans. Dating back to the Middle Pleistocene, the fossils help to fill in gaps in an intriguingly complex part of the hominid family tree.

The species Homo neanderthalensis shares an unknown common ancestor with our own species, Homo sapiens, but it’s unclear exactly when the lineages diverged. Homo sapiens evolved perhaps 300,000 years ago, according to the fossil record, while Neanderthals’ evolutionary timeline has proven even trickier to pin down. Some genetic studies suggest that their lineage split from our own as long as 650,000 years ago, but the oldest definitive fossil evidence for Neanderthals extends back only about 400,000 years.

Conventional wisdom is that Neandertals emerged around 200 thousand years ago, in Europe. The Atapuerca Sima de Los Huesos remains, which show pre-Neandertal characteristics, are about the same age as the Italian remains. It has been suggested that Homo heidelbergensis is the common ancestor to both Neandertals and modern humans but this is far from clear. The genetics suggests that Neandertals and modern humans split around 600 thousand years ago but interacted as recently as 60 to 70 thousand years ago and interbred.Modern Europeans have between 3 and 6% Neandertal genes. 

This pushes back the origins of Neandertals and further muddies the picture of when and where these groups were and how they interacted.  More puzzle pieces. 

Neandertal/Denisovan Hybrid?

As J. Lawrence Angel once said: “When two groups of people meet, they may fight, but they will always mate.”  A story is now coming out of Russia describing more research at the Denisova Cave, in the Altai Mountain region that recounts exactly what Angel was talking about.  From Richard Coniff, at Scientific American:

In a remarkable twist in the story line of early human evolution, scientists have announced the discovery of “Denisova 11”—a female who was at least 13 years old, lived more than 50,000 years ago and was a child of mixed parentage. Her parents were not just of different races, but two different and now-extinct early human types. Their exact taxonomic designations—whether they were separate species or subspecies—is still a matter of scientific debate. But the bottom line for Denisova 11 is that mom was a Neandertal and dad a Denisovan.

This is a remarkable claim, similar to the one that Erik Trinkaus made about the Lagar Velho child discovered in Portugal that is thought to be a Neandertal/modern human offspring. What evidence has been marshalled to support this claim?  In a word: genetics.  The evidence is taken from another bone fragment from the site.  From the abstract:

The father, whose genome bears traces of Neanderthal ancestry, came from a population related to a later Denisovan found in the cave. The mother came from a population more closely related to Neanderthals who lived later in Europe than to an earlier Neanderthal found in Denisova Cave, suggesting that migrations of Neanderthals between eastern and western Eurasia occurred sometime after 120,000 years ago. The finding of a first-generation Neanderthal–Denisovan offspring among the small number of archaic specimens sequenced to date suggests that mixing between Late Pleistocene hominin groups was common when they met.

So, if they interbred regularly (or regularly enough, anyway), why aren't they just one species?  Svante Paabo argues that it is because they simply did not come together very often.  To this, I would argue that they probably also had fairly distinct cultures. 

If this kind of information had come out a few decades back, there would have been quite a few squawks and naysayers but as the evidence piles up for hybridization between many different groups throughout the Pleistocene, researchers have become more accepting of it.  It is pretty clear that the evolutionary picture was a whole lot more complex than we thought. 

More Evidence of Complex Tool Creation By Archaic Homo sapiens

New excavations at Boxgrove, a site which dates from approximately 300 thousand years ago has yielded tools that show more complex creation strategies.  From the Independent:

The specific stone tools which were analysed as part of the study were sophisticated flint hand axes, which had required a special technique to shape them.

The technique is known to prehistorians as ‘platform preparation’. In most very early stone tools, the manufacturing process is a simple single-stage affair in which the toolmaker merely hits a lump of flint with a stone repeatedly to systematically knock bits off it until the lump has been reduced to a desired shape.

However, more sophisticated toolmakers employed a two-stage approach. First they would successively "soften up" small portions of the flint’s surface, so as to then be able to more accurately remove flakes from it, thus creating a much more sophisticated and effective tool with a better and more refined cutting edge.

Quite a bit of evidence is emerging that the group of hominins loosely called “archaic Homo sapiens” was considerably more technologically and socially advanced than we once thought. Whether or not they looked modern, they were beginning to act that way. 

New Homo sapiens Fossil Found in Arabia

A new fossil finger has been unearthed as Arabia that purports to be 87 ky old.  UPI is on it.

The fossil was found buried beneath the sands of the Nefud Desert, which today stretches across the Northern Arabia Peninsula. The site where the fossil was found was once home to a freshwater lake.

Around the time humans showed up, a climatic shift brought monsoons to the region, spawning grasslands. Animal fossils suggest antelope grazed the land and hippos swam in the ancient lake.

Researchers measured ratios of radioactive elements in the finger bone and compared the ratios to those found in animal fossils with confirmed dates. The analysis confirmed the age of the human fossil, the oldest found in Arabia.

"This discovery for the first time conclusively shows that early members of our species colonized an expansive region of southwest Asia and were not just restricted to the Levant," Huw Groucutt, a researcher with the University of Oxford and the Max Planck Institute for the Science of Human History, said in a news release.

How do we know it was from Homo sapiens?

Among these finds was a well preserved and small fossil, just 3.2 cm long, which was immediately recognized as a human finger bone. The bone was scanned in three dimensions and its shape compared to various other finger bones, both of recent Homo sapiens individuals and bones from other species of primates and other forms of early humans, such as Neanderthals. The results conclusively showed that the finger bone, the first ancient human fossil found in Arabia, belonged to our own species.

I do not have access to this article as neither the lab nor UT has a subscription to Nature: Ecology & Evolution. Aside: Given our focus on materials science and computing, I kind of get why ORNL does not have a subscription.  UT, not so much.  This journal should be in their wheelhouse.  According to the abstract, the find is securely dated and:

The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna.

Maddenly, there is no information in the abstract about the morphology of the find, especially given that Neandertal and early anatomically modern phalanges are remarkably similar. I am sure they were able to differentiate it, but I would sure like to know how.

Modern Humans Interbred with Two Groups of Denisovans

There is now more evidence that were were “one big happy family.”  Here is a short recap:

Beginning around 1.8 million years ago, a hominin form called Homo erectus left Africa for points east, eventually settling in Indonesia and China. These early humans were characterized by having heads roughly ¾ the size of modern humans with very large brow ridges and with their widest point just above the ears. They were also the first humans to conquer fire and perfect hunting.

Then, at some point, between 300 and 500 thousand years ago, a population group migrated from North Africa into Europe and, eventually into East Asia. The European branch became the Neandertals, between 200 and 250 thousand years ago, and the East Asian group eventually became the Denisovans. The Denisovans then spread east and south, eventually mixing with other populations, some of which were the precursors of the Melanesians and native Australians. The bulk of the Neandertals hunkered down in Europe and tried to outlast the bitter cold of not one but two glaciations.  Despite this, while often pilloried in cultural literature as being half-witted brutes, Neandertals were a very complex society, with advanced weaponry and hunting behavior, grave goods, habitation structures and who practiced ritual behavior. Some populations of Neandertals eventually  expanded their range into Western Asia and steppic Russia and interbred with the Denisovans.  Unfortunately, as a culture, we know next to nothing about the Denisovans. 

Roughly 100 thousand years after this, there was yet another wave of migration, between 100 and 60 thousand years ago, of early modern humans from North Africa, who moved north and East mixing with both the Neandertals in Europe and, perhaps, Western Asia and the Denisovans in East Asia.

And now we learn that the modern humans arriving from Africa interbred with not one but two groups of Denisovans.  From Gizmodo:

We know so little about the Denisovans that they don’t even have a formal scientific name, though scientists are considering Homo sp. Altai or Homo sapiens ssp. Denisova. Indeed, as these names suggest, Denisovans were a branch of humans, having diverged from Neanderthals some 200,000 years ago. We know this because the Altai fossil yielded a near-complete genome, which scientists have been poring over since it was first sequenced in 2010.

But in addition to the Neanderthal ancestry, genetic anthropologists also learned that Denisovan DNA lives on in modern humans, especially among Oceanians and East and South Asians. This means anatomically modern humans, or Homo sapiens, must’ve interbred with a population of Denisovans. But as new research published today in the science journal Cell points out, our ancestors mated with Denisovans on at least two different historical occasions. So the traces of Denisovan DNA embedded in the genomes of some people living today originated from at least two distinct Denisovan populations.

Given Palaeolithic population densities, this is not surprising.The research seems to indicate that there were early modern human/Denisovan mixes in both Asia and Oceania.  What this means is that, once the Denisovans and Neandertals split, the Denisovans migrated east and northeast (as humans will do) and established population centers in these areas.  When the modern humans came (Huh.  I wonder what is over that hill?  Oh look, humans...sort of.) it made sense to intermingle with them.  We already know that Neandertals and modern humans could, and did, mix.  It is, absent any knowledge to the contrary, reasonable to assume that the Denisovans looked mostly modern human. 

Interestingly, the research seems to indicate that the rate of interbreeding of Neandertals to early moderns was much more limited than with moderns and Denisovans.  This is at variance with other studies (and fossil material) which seems to indicate more sustained contact.  It would be nice if we could find a bit more fossil evidence to get a handle on what at least one Denisovan looked like. 

New BioLogos Post on the Misliya Modern Human Fossil

There is a new BioLogos post on the Israeli Misliya partial face and teeth fossil.  Comments welcome there and here.

Indian Site of Attirampakkam Pushes Middle Palaeolithic of India Back to 385 Kya

Great Googlymoogly!  Fresh on the heels of the discovery of the Misliya site (upcoming BioLogos post) that the Middle Palaeolithic Levallois technology was present in Israel as early as 194 thousand years ago, we now have news from India that places the emergence of the same technology as early as 385 thousand years ago.  From Malcolm Ritter at the site PhysOrg:

Homo sapiens arose in Africa at least 300,000 years ago and left to colonize the globe. Scientists think there were several dispersals from Africa, not all equally successful. Last week's report of a human jaw showed some members of our species had reached Israel by 177,000 to 194,000 years ago.

Now comes a discovery in India of stone tools, showing a style that has been associated elsewhere with our species. They were fashioned from 385,000 years ago to 172,000 years ago, showing evidence of continuity and development over that time. That starting point is a lot earlier than scientists generally think Homo sapiens left Africa.

This tool style has also been attributed to Neanderthals and possibly other species. So it's impossible to say whether the tools were made by Homo sapiens or some evolutionary cousin, say researchers who reported the finding Wednesday in the journal Nature.

Nowhere is there any indication that modern humans are associated with the tools at Attirampakkam (ATM). In fact, there are no hominin remains whatsoever at ATM. The Indian subcontinent has always had a paucity of human remains, the most notable of which is the Narmada Homo erectus cranium.  In Europe, the Levallois technology, which also shows up at ATM, is almost exclusively associated with Neandertals and in the Levant, at the Skhul, Qafzeh, Tabun and Amud sites in the Mt. Carmel region, it is used by both Neandertals and early moderns. Consequently, while someone was using early Middle Palaeolithic tools at ATM, we don't know who.

What is incredibly striking about the ATM site is that, from 385 ky down to 172 ky, there is continuous technological evolution, beginning with what the describers call the “terminal Acheulean,” through a punch flake industry with points, to knives.  Another point made by the authors is that this Middle Palaeolithic industry appears and flourishes during a time where other sites in India are still using Acheulean technology.  This suggests “that spatial variability among Palaeolithic cultural sequences is larger than previously thought.”  From the Nature article¹:

The behavioural transformations that mark the advent of the Indian Middle Palaeolithic at ATM are summarized by the following diagnostic features: the obsolescence of Acheulian large-flake reduction sequences, with a directional shift towards smaller tool components; the adoption and continuance of Levallois recurrent and preferential strategies; a gradual intensification of blade reduction; and an increased use of finer grained quartzite during phase II than during A gradual discontinuation of biface use—which becomes definite at ATM after approximately 172 ± 41 ka—has been reported at other Middle Palaeolithic and Middle Stone Age sites worldwide (see Supplementary Information and references therein).

This is an astounding find for so many reasons. It establishes the appearance of the Levallois technology, one we know originated in Africa, outside Africa over 150 thousand years earlier than we thought. This is a technology that was considered to have originated some 400 thousand years ago. We may now have to revise this date further into the past.

It shows a clear progression of human cultural evolution, from the late Acheulean hand axes, through Middle Palaeolithic Levallois technology to a more blade-oriented technology.  Sadly, it appears as though the site began to fall into disuse and the sequence stops cold around 74 kya.  This is not surprising since it coincides with the Toba supervolcano eruption in Indonesia.  Nonetheless, as the authors point out, it suggests multiple migrations out of Africa of first archaic Homo sapiens, then modern Homo sapiens, such as those in Misliya and that these groups interacted with the Archaic hominins they encountered along the way.

¹Akhilesh, K., Pappu, S., Rajapara, H. M., Gunnell, Y., Shukla, A. D., & Singhvi, A. K. (2018). Early Middle Palaeolithic culture in India around 385–172 ka reframes Out of Africa models. Nature, 554, 97. https://doi.org/10.1038/nature25444

Modern Humans Came Out of Africa Earlier Than Thought and Did So Multiple Times

If you have been studying human evolution, this story is not new.We have suspected for some time that humans migrated out of Africa in waves, beginning with Homo heidelbergensis, up through archaic Homo sapiens and, now, modern Homo sapiens.  As the story notes, there have likely been multiple migrations of Homo sapiens, as well. 

From the story in Science Daily:

A review of recent research on dispersals by early modern humans from Africa to Asia by researchers from the Max Planck Institute for the Science of Human History and the University of Hawai'i at Manoa confirms that the traditional view of a single dispersal of anatomically modern humans out of Africa around 60,000 years ago can no longer be seen as the full story. The analysis, published in the journal Science, reviews the plethora of new discoveries being reported from Asia over the past decade, which were made possible by technological advances and interdisciplinary collaborations, and shows that Homo sapiens reached distant parts of the Asian continent, as well as Near Oceania, much earlier than previously thought. Additionally, evidence that modern humans interbred with other hominins already present in Asia, such as Neanderthals and Denisovans, complicates the evolutionary history of our species.

Here is the graphic from the story:

 
What is only hinted at in the article is that when these waves of moderns came out of Africa, they interbred with the archaic hominins that they encountered. Further, this genome was remarkably stable, since there is genetic evidence that there was at least 500 thousand years of separation between them.Also missing from the story is the range of variation that these hybridizations display.  For example, as noted by the triangle on the map, the Xuchang fossils from China seem to show a mix of modern, Neandertal and late Homo erectus morphologies.  As I noted at the time:

The implications of these skulls are stark: there has been widespread population mixing and regional continuity in Europe and Asia for at least 400 thousand years. Not only did the Neandertals feel enough cultural kinship to mate and have children with these East Asian people, the early modern humans coming out of Africa did, as well.

The other peculiar thing about the graphic is that there seems to be no migration pattern through the strait of Gibraltar. This seems odd since this is likely at least one of the routes that were taken by H. ergaster between 1.5 and 2.0 mya, and since it is thought that the Levallois tool technology comes from the Middle Stone Age of Africa, this would have been a likely route of introduction.  There may have been a barrier of sorts, suggested by the fact that the latest surviving Neandertals are from Spain.