It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, January 31, 2020
'Stranger things!' Fisherman is left gobsmacked after hauling a freaky three-legged creature from the Atlantic Ocean
Bulbous-headed creature is seen writhing on decking off Coney Island, Brooklyn
The fisherman questions what creature it is and calls for his mother to take a look
Bizarre creature has slits for gills where eyes should be and three long tentacles
The bizarre creature has slits for gills which appear to stare down the camera like eyes.
His mother screams: 'Holy s**t! What the hell is that?'
The dumbfounded fisherman replies: 'What is happening?'
TikTok users likened the fish to Dart from Netflix series Stranger Things while another questions the creature's welfare
The odd clip was posted to TikTok by Nataliia Vorobok and has since received 1.4million likes.
People were quick to question the creature's welfare while one likened the creature to Dart in the Netflix drama, Stranger Things.
Another user said: 'Put it back in the water!!!!'
Some have said the creature is a clearnose skate which is a species of cartilaginous fish.
The diamond-shaped skate is a brown or grey colour which lives in the northwestern Atlantic and migrates inshore and out to deeper waters depending on the season.
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SPOLIER ALERT Takabuti, the famous ancient Egyptian mummy on display at the Ulster Museum, suffered a violent death from a knife attack, a team of experts from National Museums NI, University of Manchester, Queen’s University Belfast and Kingsbridge Private Hospital have revealed. TAKABUTI RHYMES WITH SHAKE YER BOOTY
Takabuti mummy case, ca. 660 BC [Credit: University of Manchester]
The team, whose findings are made public on the 185 year anniversary of Takabuti’s unwrapping in 1835, also show that her DNA is more genetically similar to Europeans rather than modern Egyptian populations.
The team show Takabuti had an extra tooth - 33 instead of 32 - something which only occurs in 0.02% of the population and an extra vertebrae, which only occurs 2% of the population.
And Takabuti’s heart, previously thought to have been missing, was identified by the state of the art technology used by the researchers as intact and perfectly preserved.
The scans show she was stabbed in the upper back near her left shoulder and that it was the cause of her death.
The findings finally solve the mystery of the mummy which has intrigued Egyptologists - and the public - since she was first unwrapped in Belfast in 1835. It transforms our understanding of Takabuti’s life in ancient Egypt and her journey into the afterlife.
The project was supported by funding from Friends of the Ulster Museum. Kingsbridge Private Hospital facilitated the work by providing their expertise and use of a portable x-ray machine to aid sampling for DNA work.
Takabuti's mummified remains [Credit: University of Manchester]
According to the team, the mysterious object in her body cavity, previously thought to be her heart, was in fact material used to pack the knife wound.
Takabuti lived over 2,600 years ago and died in her 20s. Experts say she was probably a married woman because she was a leading woman living - or mistress – who lived in a Thebes house - where Luxor is today.
She was acquired in Thebes by Thomas Greg from Holywood, County Down and brought to Belfast in 1834.
The scientific team consisted of Professor Rosalie David, Drs Bart van Dongen, Konstantina Drosou, Sharon Fraser, Professor Tony Freemont, Ds Roger Forshaw, Robert Loynes and Keith White from The University of Manchester
It also included Professors Eileen Murphy and Paula Reimar from Belfast University; Professor Caroline Wilkinson and Dr Sarah Shrimpton from Liverpool John Moores University; and Dr David Tosh from the Ulster Museum.
Dr Greer Ramsey, Curator of Archaeology at National Museums NI, says advances in scientific techniques have made the new findings possible.
Detail of Takabuti's head with auburn coloured wig deliberately set after death [Credit: University of Manchester]
He said: “There is a rich history of testing Takabuti since she was first unwrapped in Belfast in 1835. But in recent years she has undergone x-rays, CT scans, hair analysis and radio carbon dating. The latest tests include DNA analysis and further interpretations of CT scans which provides us with new and much more detailed information.
“The significance of confirming Takabuti’s heart is present cannot be underestimated as in ancient Egypt this organ was removed in the afterlife and weighed to decide whether or not the person had led a good life. If it was too heavy it was eaten by the demon Ammit and your journey to the afterlife would fail.”
The tests and examination of Takabuti were carried out over a period of months by the team using the latest scanning technologies, leading to new insights into Egyptian high society in the 25th dynasty.
Professor Rosalie David, an Egyptologist from The University of Manchester said: “This study adds to our understanding of not only Takabuti, but also wider historical context of the times in which she lived: the surprising and important discovery of her European heritage throws some fascinating light on a significant turning-point in Egypt’s history.
“This study, which used cutting-edge scientific analysis of an ancient Egyptian mummy - demonstrates how new information can be revealed thousands of years after a person’s death. Our team - drawn from institutions and specialisms – was in a unique position to provide the necessary expertise and technology for such a wide-ranging study.”
Professor Eileen Murphy, a Bioarchaeologist from Queen’s University Belfast’s School of Natural and Built Environment, said: “It has been an incredible privilege to have been involved in modern research that has really helped enlighten us about Takabuti’s life and death. The latest research programme has provided some astounding results. It is frequently commented that she looks very peaceful lying within her coffin but now we know that her final moments were anything but and that she died at the hand of another.
Takabuti's opened coffin [Credit: University of Manchester]
“Trawling the historical records about her early days in Belfast it is clear that she caused quite a media sensation in 1835 – she had a poem written about her, a painting was made of her prior to her ‘unrolling’ and accounts of her unwrapping were carried in newspapers across Ireland. Research undertaken ten years ago gave us some fascinating insights, such as how her auburn hair was deliberately curled and styled. This must have been a very important part of her identity as she spurned the typical shaven-headed style. Looking at all of these facts, we start to get a sense of the petite young woman and not just the mummy.”
Retired Orthopaedic Surgeon and currently honorary lecturer in the University of Manchester's KNH Centre for Biomedical Egyptology, Dr Robert Loynes who performed the CT analysis and biopsy retrieval of material for a DNA and other analyses said: “The CT scan reveals that Takabuti sustained a severe wound to the back of her upper left chest wall. This almost certainly caused her rapid death. However, the CT scan also reveals unusual and rare features of her embalming process.”
Geneticist Dr Konstantina Drosou said “Takabuti’s genetic footprint H4a1 is relatively rare as it has not been found to my knowledge in any ancient or modern Egyptian population. My results agree with previous studies about ancient Egyptians being more genetically similar to Europeans than modern day Arabs.”
A book is currently being produced by the project team and supported by the Engaged Research Fund, Queen’s University Belfast, and the KNH Centre for Biomedical Egyptology, The University of Manchester. The book will bring together all of the research findings to date on Takabuti.
Details of the new findings can be found in the Ancient Egypt gallery in the Ulster Museum where Takabuti is currently on display. Admission is free.
The earliest humans in North America were far more diverse than previously realized, according to a new study of human remains found within one of the world's most extensive underwater cave systems.
The remans, discovered in the caverns of the Mexican state of Quintana Roo, represent just four of the earliest North Americans, all of whom lived between 9,000 and 13,000 years ago. They're important because North American remains from the first millennia of human habitation in the Americas are rare, said study leader Mark Hubbe, an anthropologist at The Ohio State University. Fewer than two dozen individuals have been discovered, he added.
What makes the four individuals from Mexico interesting is that none of them are quite alike. One resembles peoples from the Arctic, another has European features and one looks much like early South American skulls, while the last doesn't share features with any one population.
"The differences we see among these Mexican skulls are on the same magnitude as the most different populations [globally] nowadays," Hubbe told Live Science.
The settlement of the Americas is a complicated topic, shrouded in mystery because of the dearth of archaeological findings from 15,000 to 20,000 years ago, which is probably when the first humans set foot on the continent. South America has more early human remains than North America, Hubbe said. The skulls found in South America are typically quite similar to one another, sharing features of skull measurements with indigenous Australians and Africans.
This doesn't mean that the South Americans had ancestors who came directly from Australia or Africa, Hubbe cautions. Rather, the shared features reveal a shared common ancestry between ancient South Americans and the peoples of Australia and Africa.
"The [skull] morphologies in Asia changed a lot in the last 10,000 years," Hubbe said. "Everyone who came [to the Americas] before 10,000 years ago would look a lot like early modern humans out of Africa and Australia."
Because the path to South America must have included pit stops in North America or along the Pacific coast, the assumption has long been that early people in South America looked a lot like early people in North America. But the new research suggests otherwise, Hubbe said. Instead, early North American populations look far more diverse than early South American populations.
"For whatever reason, when they went to South America, part of this diversity disappeared," Hubbe said.
The extensive caves of Quintana Roo are now mostly underwater. But about 12,000 years ago, during the end of the Pleistocene epoch and the beginning of the Holocene, sea levels were lower and the caves were dry. Some of the early inhabitants of Mexico seemed to use the caves as burial places, deliberately placing bodies inside. Some other skeletons discovered in the caves appear to indicate that those people's deaths may have been accidental.
Of the four skulls studied in the new research, published today in the journal PLOS ONE, one came from a young adult woman who lived around 13,000 years ago; one belonged to a young adult male from the same era; one was from a middle-aged woman who lived between about 9,000 and 12,000 years ago; and the fourth was that of a middle-aged man from around 10,000 years ago. Hubbe and his co-authors used computed tomography (CT) scanning to re-create digital, 3D images of the skulls. They then marked various landmarks on the skulls, such as the bottom of the nose or top of the eye orbits. Sizes and distances between landmarks were then used to compare the skulls to larger data sets of measurements from different populations of people around the world.
There are limitations to working with the data of only four people, Hubbe said – after all, any given individual can be an outlier compared with the rest of his or her community. But, in an attempt to downplay any individual quirks of the skulls, the researchers focused only on the components of the measurements that explained the majority of the variations between skulls. By limiting the analysis to only major variations, they could avoid putting too much weight on smaller differences between skulls.
They found that the 13,000-year-old young woman had features that most closely matched Arctic North Americans from Greenland and Alaska. The young man from 13,000 years ago, on the other hand, looked most similar to people from European populations. The middle-aged female from between 9,000 and 12,000 years ago looked much like the earliest settlers of South America. Finally, the middle-aged man from around 10,000 years ago showed no clear pattern. He had features seen in several American and Asian populations.
The findings are important because they provide new information on the earliest Americans, said Richard Jantz, an anthropologist at the University of Tennessee who was not involved in the research. The skulls are diverse, he said, though he noted that all but the young man from 13,000 years ago had Asian or Native American affinities, so the differences shouldn't be overexaggerated.
The new information complicates the fuzzy picture of who the first Americans were and how the earliest migrations worked.
North America could have been more diverse than South America if there were a consistent flow of people – and new genes – into North America, but only one or two big movements of populations through the funnel of Mexico into South America, Hubbe said.
"We cannot test this at this point," he said.
That story also contradicts the genomic data researchers have collected. Genomics suggest that all Native Americans (with the exception of a few later migrants) descend from a single migration of people from Asia. But research based on phenotype – the way people looked – suggests multiple migration events, creating a population that got regular injections of diversity.
"I think if America consisted of a homogenous population 10,000 or 15,000 years ago, that drawing skulls at random from it would not produce as much variation as you see," Jantz said.
In today's humans, Jantz said, genomics data and skull shape data generally mesh well — people with similar ancestry tend to show similarities in their skull measurements. So far, the same does not seem to be the case for the earliest Americans. But there are limitations in data on both the genetic and the archaeological side, Jantz said. Genomics researchers have only three ancient DNA samples from North America, and modern Native Americans' genetic profiles have been complicated by genocide and mixture with Europeans. Researchers who study skull morphology have only a handful of bones to work with, as well.
"To me," Jantz said, "the biggest challenge is reconciling conflicting lines of evidence."
Ancient Assyrian rock carvings unearthed in Iraq after narrowly avoiding destruction by ISIS show a king surrounded by gods astride mythical beasts Assyrian rock carvings are the first of their kind found in 150 years Archaeologists abandoned the dig in 2014 as ISIS was just 15 miles away Following ISIS defeat, experts returned to the site in Iraq to finish excavations Found rock carvings of an Assyrian king paying homage to the gods and surrounded by mythical creatures
Ancient carvings of an Assyrian king honouring the gods while surrounded by mythical beasts have been safely unearthed in Iraq after being threatened by ISIS.
ISIS seized the city of Mosul in 2014 and researchers were forced to abandon the archaeological site of Faida as the ruthless force was just 15 miles away.
The ten rock reliefs were found in the Kurdistan region of Iraq and are believed to be the first of their kind discovered in 150 years.
Archaeologists surveyed the site in 2012 and it was only late last year, with the self-proclaimed caliphate overthrown, that archaeologists were able to return and excavate the treasures left behind.
See the rare Assyrian carvings uncovered in Iraq after ISIS defeat
Ancient carvings menaced by the advance of ISIS have finally been revealed after the terror group's defeat, in the first discovery of its kind for more than 150 years The ten rock reliefs depict Assyrian gods riding mythical creatures in procession with the king (pictured)
Italian and Iraqi archaeologists uncovered the reliefs 12 miles (20km) south of the Kurdistani city of Duhok.
Expedition leader, Daniele Morandi Bonacossi of the University of Udine in Italy, said nothing like the carvings had been found since 1845.
'Assyrian rock reliefs are extremely rare,' he said.
'There is no other Assyrian rock art complex that can be compared with this one, with the only exception being Khinis, in the north-eastern part of the region.'
ISIS, or Islamic State, was remorseless in destroying antiquities it felt were idolatrous, though it also looted artifacts to sell. At the height of its powers, its fighters were only 15 miles from the dig site.
But even now, with ISIS defeated, the rock carvings face fresh threats.
'The most serious threats are vandalism, illegal excavations and the activities of the nearby village that are literally besieging the site,' said Professor Bonacossi.
'One of the reliefs was illegally excavated and thereby damaged in May 2019, and the owner of one farmstead has partly destroyed one of the reliefs in order to expand his cow stable.
'The only way to protect the site is to fence it off and guarantee a constant security service controlling the area.
'The Duhok Governorate is committed to guarantee the protection of the reliefs.'
Italian and Iraqi archaeologists uncovered the reliefs 12 miles (20km) south of the Kurdistani city of Duhok Archaeologists surveyed the site in 2012 and it was only late last year, with the self-proclaimed caliphate overthrown, that archaeologists were able to return and excavate the treasures left behind
The reliefs (pictured) once decorated the banks of the Faida irrigation canal, which was part of a vast network that brought water to the Assyrian capital, Nineveh. The canal was likely built during the reign of Sargon II
Among the deities depicted is Ashur, the main Assyrian god, his wife Mullissu, the moon god Sin and the sun god Shamash. They are shown astride mythical beasts including dragons and horned lions (pictured)
The reliefs once decorated the banks of the Faida irrigation canal, which was part of a vast network that brought water to the Assyrian capital, Nineveh.
The canal was likely built during the reign of Sargon II, whose successor, Sennacherib, is believed to have incorporated it into the wider network.
Both kings are named in the Bible for their military exploits, with the former conquering the Kingdom of Israel.
The figures on the panels are shown in profile, facing left, in the direction the water would have flowed.
Among the deities depicted is Ashur, the main Assyrian god, his wife Mullissu, the moon god Sin and the sun god Shamash.
They are shown astride mythical beasts including dragons and horned lions.
'The reliefs tell us that the construction of this local irrigation system was celebrated by royal power through the carving of rock reliefs,' said Professor Bonacossi.
The excavation of impressive irrigation systems across the core region of the Assyrian empire changed the economic foundation of the regions involved.
'It transformed them from extensive dry-farming regions into highly-productive irrigation agriculture areas.
'But it also profoundly modified the space and settlement patterns in the core of the Assyrian empire.'
Professor Bonacossi believes the site could hold more secrets still.
'During the excavation of one relief, we found another which was not visible at the surface,' he said.
'This means that probably many other reliefs are still to be found and that this rock art complex is larger than we expected.
'This explains why the Faida archaeological site is so important.' Archaeologists surveyed the site in 2012 (pictured), following up on an earlier British excavation in 1973, but the project ground to a halt when ISIS captured the nearby city of Mosul in 2014
WHAT WAS THE ASSYRIAN EMPIRE?
The Assyrian Empire was a complex Mesopotamian civilisation dating from 2,500 BC to around 600 BC.
Mesopotamia, an area of ancient Asia, was where people first gathered in large cities, created governments, and learned to write.
Alongside other Mesopotamian groups like ancient Babylon and the Sumerian cities, the Assyrian Empire was one of the earliest civilisations in history.
As its height, the empire stretched from Egypt up through what is now Syria, Iraq, Lebanon and into Turkey. +8
As its height, the Assyrian Empire (red) stretched from Egypt up through what is now Syria, Iraq, Lebanon and into Turkey
Turkey's Kültepe district was home to a settlement of the Old Assyrian Empire from the 21st to 18th centuries BC.
Over 1,000 cuneiform tablets were found in the area in 1925, revealing a rich and complex cultural heritage.
Much of our knowledge of early human societies comes from stone tablets such as these, leading some scholars to label Mesopotamia 'the place where history began'.
these remarks by Toni Negri on postmodern fascism - published in 1996 - in his Constituent Republic essay are quite perceptive.
Postmodern fascism seeks to attach itself to the realities of post-Fordist labour cooperation, and seeks at the same time to express some of its essence in a form that is turned on its head. In the same way the old fascism mimicked the mass organisational forms of socialism and attempted to transfer the proletariat's impulse toward collectivity into nationalism (national socialism or the Fordist constitution), so postmodern fascism seeks to discover the communist needs of the post-Fordist masses and transform them, gradually, into a cult of differences, the pursuit of individual differences, and the search for identity - all within a project of creating overriding despotic hierarchies aimed at constantly, relentlessly, pitting differences, singularities, identities, and individualities one against the other. Whereas communism is respect for and synthesis of singularities, and as such desired by all those who love peace, the new fascism (as an expression of the financial command of international capital) would produce a war of all against all; it would create religiosity and wars of religion, nationalism and wars of nations, corporative egos and economic wars. (Constituent Republic, in Paolo Virno and Michael Hardt (eds) Radical Thought in Italy, p.216)
I WAS IMPRESSED WITH THE QUOTE AND THE SOURCE ESSAY I DIDN'T HAVE UNTIL NOW THANKS TO PHIL AT ALL THAT IS SOLID
We're all a little more Neanderthal than we thought: Study claims ancient Europeans introduced Neanderthal DNA to African populations 30,000 years ago
Study found the first conclusive evidence for Neanderthal DNA in Africans
Neanderthal DNA previously only found in Americans, Europeans and Asians
Neanderthals and humans hybridised after Homo sapiens migrated out of Africa
Ancient Europeans descended from these events then migrated back into Africa
Mating between these European migrants and native Africans passed trace amounts of Neanderthal DNA into their genes
Scientists have found, for the first time, conclusive evidence that Neanderthal DNA exists in modern-day Africans.
A new study by Princeton University reveals that African people — who were previously thought to have no Neanderthal DNA — got around 0.3 per cent of their genes from our ancient ancestors.
African people obtained a sliver of Neanderthal DNA after breeding with humans, who migrated to Africa from Europe around 30,000 years ago.
Ancestors of these Europeans are known to have bred with Neanderthals around 20,000 years earlier, providing an indirect pathway for Neanderthal DNA into Africans.
The new study shows that native Europeans, Asians, Africans and Americans all have some Neanderthal DNA - and non-Africans have even more than previously assumed.
Scroll down for video
Study finds previous assumptions that Africans did not breed with Neanderthals direct
ly are true, but they inadvertently received Neanderthal DNA from those who originated in parts of the world whose ancestors had mated with Neanderthals (pictured, the two stages which led to Neanderthal DNA being found in Africans)
Neanderthals disappeared around 40,000 years ago but their DNA lives on in modern humans thanks to interbreeding between the two species (file photo)
TIMELINE OF HOW NEANDERTHAL DNA REACHED AFRICA
100,000 years ago - A large wave of migration out of Africa occurred
50,000 years ago - Parts of this Homo sapiens population mated with Neanderthals
DNA from Neanderthals was then passed down the generations, becoming steadily more diluted
30,000 years ago - European and East Asian populations split
Some Europeans then migrated back into Africa where they mated with native Africans
Neanderthal DNA was then passed into future generations of Africans from the European lineage
Dr Aaron Wolf, study author from the University of Washington, told MailOnline: 'We believe a large portion of the Neanderthal ancestry in African populations is due to historic back-migration from an ancestral European population into Africa.'
Around 100,000 years ago, a large wave of migration out of Africa occurred, from which the vast majority of modern non-African populations are descended.
Parts of this population interbred with Neanderthals - around 50,000 years ago - and passed Neanderthal DNA onto today's human populations.
'We believe some of this Neanderthal carrying non-African population returned to Africa, and introduced Neanderthal DNA into African populations,' said Dr Wolf.
'Importantly, we believe this happened after the split of the European and East Asian populations (~30,000 years ago).'
Scientists identified regions of Neanderthal ancestry in Africans for the first time by identifying, on average, 17 megabases (Mb) of Neanderthal DNA per individual.
This corresponds to approximately 0.3 per cent of the African peoples' genome stemming from the Neanderthals, who went extinct around 40,000 years ago.
This is significantly less than the levels of Neanderthal ancestry in Europeans (51 Mb/individual), East Asians (55 Mb/individual), and South Asians (55 Mb/individual).
East Asians, who were thought to have 20 per cent more Neanderthal DNA than Europeans, actually only have 8 per cent more, the scientists discovered.
'This suggests that most of the Neanderthal ancestry that individuals have today can be traced back to a common hybridisation event involving the population ancestral to all non-Africans, occurring shortly after the Out-of-Africa dispersal,' Dr Joshua Akey of Princeton University and study author says.
The study confirms previous assumptions that Africans did not breed with Neanderthals directly.
However, it shows that they inadvertently received Neanderthal DNA from those who originated in parts of the world whose ancestors had mated with Neanderthals.
'I am struck by the fact that we often conceptualise human history in very simple terms,' Dr Akey says.
'For example, we often imagine there was a single dispersal out of Africa that happened 60,000 to 80,000 years ago that led to the peopling of the world.
'However, our results show this history was much more interesting and there were many waves of dispersal out of Africa, some of which led to admixture between modern humans and Neanderthals that we see in the genomes of all living individuals today.'
WHO WERE THE NEANDERTHALS?
The Neanderthals were a close human ancestor that mysteriously died out around 50,000 years ago.
The species lived in Africa with early humans for hundreds of millennia before moving across to Europe around 500,000 years ago.
They were later joined by humans taking the same journey some time in the past 100,000 years.
The Neanderthals were a cousin species of humans but not a
direct ancestor - the two species split from a common ancestor - that perished around 50,000 years ago. Pictured is a Neanderthal museum exhibit
These were the original 'cavemen', historically thought to be dim-witted and brutish compared to modern humans.
In recent years though, and especially over the last decade, it has become increasingly apparent we've been selling Neanderthals short.
A growing body of evidence points to a more sophisticated and multi-talented kind of 'caveman' than anyone thought possible.
It now seems likely that Neanderthals buried their dead with the concept of an afterlife in mind.
Additionally, their diets and behaviour were surprisingly flexible.
They used body art such as pigments and beads, and they were the very first artists, with Neanderthal cave art (and symbolism) in Spain apparently predating the earliest modern human art by some 20,000 years.
African people — who were previously thought to have no
Neanderthal DNA — got 0.3 per cent of their genes from our
ancient ancestors. This breakthrough means scientists have
now discovered native Europeans, Asians, Africans and
Americans all have some Neanderthal DNA
In a study published in the journal Cell, Princeton University researchers used a computational method, called IBDmix, to assess the DNA of 2,504 modern Africans and non-Africans.
The method looks for sections of DNA in two individuals that is identical which implies they once shared a common ancestor.
Co-first author Lu Chen, a postdoctoral research associate at Princeton's Lewis-Sigler Institute for Integrative Genomics (LSI), said: 'This is the first time we can detect the actual signal of Neanderthal ancestry in Africans.
'And it surprisingly showed a higher level than we previously thought.'
Scientists then used the principle of IBD — identity by descent — to identify Neanderthal DNA in the human genome.
The new method uses characteristics of the Neanderthal sequence itself to distinguish shared ancestry from recent interbreeding.
Researchers were able to identify Neanderthal ancestry in Africans for the first time and estimate that Europeans and Asians to have more equal levels of Neanderthal ancestry than previously thought.
It adds that some of the detected Neanderthal ancestry in Africans was actually due to human DNA introduced into the Neanderthal genome.
While researchers acknowledged the limited number of African populations they analysed, they hope their new method and their findings will encourage more study of Neanderthal ancestry across Africa and other populations.
WHAT DO WE KNOW ABOUT HUMANKIND'S JOURNEY OUT OF AFRICA?
The traditional view
The traditional 'Out of Africa' model suggests that modern humans evolved in Africa and then left in a single wave around 60,000 years ago.
The model often holds once modern humans left the continent, a brief period of interbreeding with Neanderthals occurred.
This explains why individuals of European and Asian heritage today still have ancient human DNA.
There are many theories as to what drove the downfall of the Neanderthals.
Experts have suggested that early humans may have carried tropical diseases with them from Africa that wiped out their ape-like cousins.
Others claim that plummeting temperatures due to climate change wiped out the Neanderthals.
The predominant theory is that early humans killed off the Neanderthal through competition for food and habitat.
How the story is changing in light of new research
Recent findings suggest that the 'Out of Africa' theory does not tell the full story of our ancestors.
Instead, multiple, smaller movements of humans out of Africa beginning 120,000 years ago were then followed by a major migration 60,000 years ago.
Most of our DNA is made up of this latter group, but the earlier migrations, also known as 'dispersals', are still evident.
This explains recent studies of early human remains which have been found in the far reaches of Asia dating back further than 60,000 years.
For example, H. sapiens remains have been found at multiple sites in southern and central China that have been dated to between 70,000 and 120,000 years ago.
Other recent finds show that modern humans reached Southeast Asia and Australia prior to 60,000 years ago.
Based on these studies, humans could not have come in a single wave from Africa around this time, studies have found.
Instead, the origin of man suggests that modern humans developed in multiple regions around the world.
The theory claims that groups of a pre-human ancestors made their way out of Africa and spread across parts of Europe and the Middle East.
From here the species developed into modern humans in several places at once.
The argument is by a new analysis of a 260,000-year-old skull found in Dali County in China's Shaanxi Province.
The skull suggests that early humans migrated to Asia, where they evolved modern human traits and then moved back to Africa.
When the first Neanderthal genome was sequenced, using DNA collected from ancient bones, it was accompanied by the discovery that modern humans in Asia, Europe and America inherited approximately 2% of their DNA from Neanderthals -- proving humans and Neanderthals had interbred after humans left Africa. Since that study, new methods have continued to catalogue Neanderthal ancestry in non-African populations, seeking to better understand human history and the effects of Neanderthal DNA on human health and disease. A comparable catalogue of Neanderthal ancestry in African populations, however, has remained an acknowledged blind spot for the field due to technical constraints and the assumption that Neanderthals and ancestral African populations were geographically isolated from each other.
A team of Princeton researchers led by Joshua Akey found that that African individuals have considerably more Neanderthal ancestry than previously thought, which was only observable through the development of new methods [Credit: Matilda Luk, Princeton University]
In a paper published in the journal Cell, a team of Princeton researchers detailed a new computational method for detecting Neanderthal ancestry in the human genome. Their method, called IBDmix, enabled them for the first time to search for Neanderthal ancestry in African populations as well as non-African ones. The project was led by Joshua Akey, a professor in Princeton's Lewis-Sigler Institute for Integrative Genomics (LSI).
"This is the first time we can detect the actual signal of Neanderthal ancestry in Africans," said co-first author Lu Chen, a postdoctoral research associate in LSI. "And it surprisingly showed a higher level than we previously thought," she said.
The method the Princeton researchers developed, IBDmix, draws its name from the genetic principle "identity by descent" (IBD), in which a section of DNA in two individuals is identical because those individuals once shared a common ancestor. The length of the IBD segment depends on how long ago those individuals shared a common ancestor. For example, siblings share long IBD segments because their shared ancestor (a parent) is only one generation removed. Alternatively, fourth cousins share shorter IBD segments because their shared ancestor (a third-great grandparent) is several generations removed.
The Princeton team leveraged the principle of IBD to identify Neanderthal DNA in the human genome by distinguishing sequences that look similar to Neanderthals because we once shared a common ancestor in the very distant past (~500,000 years ago), from those that look similar because we interbred in the more recent present (~50,000 years ago). Previous methods relied on "reference populations" to aid the distinction of shared ancestry from recent interbreeding, usually African populations believed to carry little or no Neanderthal DNA. However, this reliance could bias estimates of Neanderthal ancestry depending on which reference population was used.
The Princeton researchers termed IBDmix a "reference free method" because it does not use an African reference population. Instead, IBDmix uses characteristics of the Neanderthal sequence itself, like the frequency of mutations or the length of the IBD segments, to distinguish shared ancestry from recent interbreeding. The researchers were therefore able to identify Neanderthal ancestry in Africans for the first time and make new estimates of Neanderthal ancestry in non-Africans, which showed Europeans and Asians to have more equal levels than previously described.
Kelley Harris, a population geneticist at the University of Washington who was not involved in the study, noted that the new estimates of Neanderthal ancestry using IBDmix highlight the technical problem in methods reliant on reference panels. "We might have to go back and revisit a bunch of results from the published literature and evaluate whether the same technical issue has been throwing off our understanding of gene flow in other species," she said.
In addition to identifying Neanderthal ancestry in African populations, the researchers described two revelations about the origin of the Neanderthal sequences. First, they determined that the Neanderthal ancestry in Africans was not due to an independent interbreeding event between Neanderthals and African populations. Based on features of the data, the research team concluded that migrations from ancient Europeans back into Africa introduced Neanderthal ancestry into African populations.
Second, by comparing data from simulations of human history to data from real people, the researchers determined that some of the detected Neanderthal ancestry in Africans was actually due to human DNA introduced into the Neanderthal genome. The authors emphasized that this human-to-Neanderthal gene flow involved an early dispersing group of humans out of Africa, occurring at least 100,000 years ago -- before the Out-of-Africa migration responsible for modern human colonization of Europe and Asia and before the interbreeding event that introduced Neanderthal DNA into modern humans. The finding reaffirmed that hybridization between humans and closely related species was a recurrent part of our evolutionary history.
While the Princeton researchers acknowledged the limited number of African populations they were able to analyze, they hope their new method and their findings will encourage more study of Neanderthal ancestry across Africa and other populations. Regarding the overall significance of the research, Chen said: "This demonstrates the remnants of Neanderthal genomes survive in every modern human population studied to date."
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