The brains of Neanderthals and modern humans developed differently
09 November 2010 Max-Planck-Gesellschaft
Researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany have documented species differences in the pattern of brain development after birth that are likely to contribute to cognitive differences between modern humans and Neanderthals.
Whether cognitive differences exist between modern humans and Neanderthals is the subject of contentious disputes in anthropology and archaeology. Because the brain size range of modern humans and Neanderthals overlap, many researchers previously assumed that the cognitive capabilities of these two species were similar. Among humans, however, the internal organization of the brain is more important for cognitive abilities than its absolute size is. The brain’s internal organization depends on the tempo and mode of brain development.
Based on detailed measurements of internal shape changes of the braincase during individual growth, a team of scientists from the MPI has shown that these are differences in the patterns of brain development between humans and Neanderthals during a critical phase for cognitive development.
Discussions about the cognitive abilities of fossil humans usually focus on material culture (e.g. the complexity of the stone tool production process) and endocranial volumes. "The interpretation of the archaeological evidence remains controversial, and the brain-size ranges of Neanderthals and modern humans overlap," says Jean-Jacques Hublin, director of the Department of Human Evolution at the MPI-EVA in Leipzig where the research was conducted. Hublin adds, "our findings show how biological differences between modern humans and Neanderthals may be linked to behavioural differences inferred from the archaeological record."
Nature of the evidence: As the brain does not fossilize, for fossil skulls, only the imprints of the brain and its surrounding structures in the bone (so called "endocasts") can be studied. The researchers used state-of-the-art statistical methods to compare shape changes of virtual endocasts extracted from computed-tomographic scans. The distinct globular shape of the braincase of adult Homo sapiens is largely the result of a brain development phase that is not present in Neanderthals.
One of the key pieces of evidence was the skull reconstruction of a Neanderthal newborn. In 1914, a team of French archaeologists had excavated the skeleton of a Neanderthal baby at the rock shelter of Le Moustier in the Dordogne. The original bones of the skeleton had been lost to science for more than 90 years, until they were rediscovered among museum collections by Bruno Maureille and the museum staff. The restored original baby bones are now on permanent display at the Musée National de Préhistoire in Les Eyzies-de-Tayac-Sireuil. The museum’s director Jean-Jacques Cleyet-Merle made it possible to scan the delicate fragments using a high-resolution computed-tomographic scanner (µCT). Using computers at the Max Planck Institute’s virtual reality lab in Leipzig, Philipp Gunz and Simon Neubauer then reconstructed the Neanderthal baby from the digital pieces, like in a three-dimensional jigsaw puzzle. "When we compare the skulls of a Neanderthal and a modern human newborn, the Neanderthal’s face is already larger at the time of birth. However, most shape differences of the internal braincase develop after birth," explains Gunz. Both Neanderthals and modern human neonates have elongated braincases at the time of birth, but only modern human endocasts change to a more globular shape in the first year of life. Modern humans and Neanderthals therefore reach large adult brain sizes via different developmental pathways.
In a related study the same team of MPI researchers had previously shown that the developmental patterns of the brain were remarkably similar between chimpanzees and humans after the first year of life, but differed markedly directly after birth. "We interpret those aspects of development that are shared between modern humans, Neanderthals, and chimpanzees as conserved," explains Simon Neubauer. "This developmental pattern has probably not changed since the last common ancestor of chimpanzees and humans several million years ago." In the first year of life, modern humans, but not Neanderthals, depart from this ancestral pattern of brain development.
Establishing when the species differences between Neanderthal and modern human adults emerge during development was critical for understanding whether differences in the pattern of brain development might underlie potential cognitive differences. As the differences between modern humans and Neanderthals are most prominent in the period directly after birth, they likely have implications for the neuronal and synaptic organization of the developing brain.
The development of cognitive abilities during individual growth is linked to the maturation of the underlying wiring pattern of the brain; around the time of birth, the neural circuitry is sparse in humans, and clinical studies have linked even subtle alterations in early brain development to changes in the neural wiring patterns that affect behaviour and cognition. The connections between diverse brain regions that are established during this period in modern humans are important for higher-order social, emotional, and communication functions. It is therefore unlikely that Neanderthals saw the world as we do.
The new study shows that modern humans have a unique pattern of brain development after birth, which separates us from our closest relatives, the Neanderthals. This uniquely modern human pattern of early brain development is particularly interesting in light of the recent breakthroughs in the Neanderthal genome project. A comparison of Neanderthal and modern human genomes revealed several regions with strong evidence for positive selection within Homo sapiens, i.e. the selection occurred after the split between modern humans and Neanderthals. Three among these are likely to be critical for brain development, as they affect mental and cognitive development.
"Our findings have two important implications," says Philipp Gunz. "We have discovered differences in the patterns of brain development that might contribute to cognitive differences between modern humans and Neanderthals. Maybe more importantly, however, this discovery will tell us more about our own species than about Neanderthals; we hope that our findings will help to identify the function of some genes that show evidence for recent selection in modern humans."
Fertile Crescent farmers took DNA to Germany
Wednesday, 10 November 2010 Rebecca Jenkins
DNA evidence suggests that immigrants from the Ancient Near East brought farming to Europe, and spread the practice to the region's hunter-gatherer communities, according to Australian-led research.
A genetic study of ancient DNA, published in PLoS Biology today, adds crucial information to the long-running debate about how farming was introduced to Europe's nomadic hunter-gatherer societies almost 8000 years ago.
An international research team, led by University of Adelaide experts, compared ancient DNA from the remains of Early Neolithic farmers at a burial site in central Germany with a large genetic database of European and Eurasian populations.
They found that these early farmers had a unique and characteristic genetic signature, suggesting "significant demographic input from the Near East during the onset of farming".
Sometimes referred to as the Fertile Crescent, the Near East would include modern-day Iraq, Jordan, Syria and Lebanon, says study leader Dr Wolfgang Haak, genographic project senior research associate at the Australian Centre for Ancient DNA at the University of Adelaide.
The revolutionary element of this study was the addition of ancient DNA , explains Professor Alan Cooper, director of the Centre for Ancient DNA, as previously researchers could only use genetic data from modern populations to examine this question.
"We have never had a detailed genetic view of one of these early farming populations - there's been a lot of inference around it... but it's all been guesswork" he says.
Migration from Anatolia and near East
Using the new high-precision ancient DNA analysis, researchers were also able to determine a possible migration route the farmers took from the Near East and Anatolia into Central Europe.
Farming first originated about 11,000 years ago in the Near East and then spread across Europe during the Neolithic period, the researchers explain.
"Whether it was mediated by incoming farmers or driven by the transmission of innovative ideas and techniques remains a subject of continuing debate in archaeology, anthropology, and human population genetics," they write in PLoS Biology.
"[This] really answers this long-running debate about whether people picked up ideas or picked up and moved", says Cooper.
Haak says these latest findings might not completely settle the debate on the origins of farming in Europe, but they would "push it in a certain direction".
Haak is keen to see other research teams build on this proof of concept study, building a picture about this transitional period in other regions and helping to put the pieces of the jigsaw together globally.
Meanwhile, Haak and colleagues at the Australian Centre for Ancient DNA want to discover how communities in this region in central Germany evolved over the next 3000 to 4000 years leading up to the Bronze Age.
"The early farmers are still quite different to modern day populations from the same region," he says, "so that means something must have happened after that."
The project involved researchers from the University of Mainz and State Heritage Museum in Halle, Germany, the Russian Academy of Sciences and members of the National Geographic Society's Genographic Project.
Early Cities Spurred Evolution of Immune System?
"Amazing" DNA results show benefits of ancient urbanization, study says.
Matt Kaplan for National Geographic News
Published November 8, 2010
As in cities today, the earliest towns helped expose their inhabitants to inordinate opportunities for infection—and today their descendants are stronger for it, a new study says.
"If cities increase the amount of disease people are exposed to, shouldn't they also, over time, make them natural places for disease resistance to evolve?" asked study co-author Mark Thomas, a biologist at University College London.
It's basic evolutionary theory: People who survive infection stand a better chance of having children and passing along disease-resistant genes. So groups from regions where urbanization has existed for thousands of years should be more disease resistant.
To do so, study co-author Ian Barnes, a molecular paleobiologist at University College London, screened DNA samples from 17 groups long associated with particular regions of Europe, Asia, and Africa—for example Anatolian Turks and the southern Sudanese.
Barnes analyzed the DNA samples for a gene associated with resistance to tuberculosis (TB) and suspected of being associated with resistance to leprosy as well as to leishmaniasis, a reaction to sand fly bites, and to Kawasaki disease, a childhood ailment that involves inflamed blood vessels and can lead to heart disease. (See "Oldest Human TB Case Found in 500,000-Year-Old Fossil.")
At the same time, the team studied archaeological and historical data to work out where the earliest cities were on these regions. For example, in Anatolia the Çatal Hüyük settlement is roughly 8,000 years old, while in southern Sudan, the city of Juba (map) isn't even a hundred.
(Related: "Half of Humanity Will Live in Cities by Year's End" [March 2008].)
In areas of ancient urbanization, it turned out, "we found very high frequency" for the TB-resistance gene, study co-author Thomas said. But, for example, "the Saami people from northern Scandinavia and the Malawi people from Africa, who have little history of urban living, did not have this frequency. (See our interactive Genographic atlas of ancient human migrations.)
"We were utterly amazed by how strongly the statistics supported what we were seeing," he added. "When you look for things like this in evolutionary history, there's so much over the years that can mess up your data."
"It's a good study and the findings make a lot of sense," said epidemiologist Andrew Read. But it also raises more questions.
"That it took the rise of disease-ridden cities to cause this resistant gene to become common suggests to me that there must be a cost to having it—or else it would have been common in the first place," said Read, of Pennsylvania State University, who wasn't involved in the new study.
Perhaps, he said, the resistant gene causes immune systems to overreact—and attack the body when it's exposed to harmless things like peanuts and pollen—making people more vulnerable to allergies and arthritis, for example.
And while it may be small consolation to the allergic and arthritic, having those disorders, Read said, might be a small price to pay for avoiding death by tuberculosis.
Also see: "Future Humans: Four Ways We May, or May Not, Evolve" >>
Findings published online September 23 by the journal Evolution.
Stone age etchings found in Amazon basin as river levels fall
Drought in Brazil reveals engravings up to 7,000 years old – evidence of ancient civilisation
Tom Phillips in Rio de Janeiro
guardian.co.uk, Wednesday 10 November 2010 16.36 GMT
A series of ancient underwater etchings has been uncovered near the jungle city of Manaus, following a drought in the Brazilian Amazon.
The previously submerged images – engraved on rocks and possibly up to 7,000 years old – were reportedly discovered by a fisherman after the Rio Negro, a tributary of the Amazon river, fell to its lowest level in more than 100 years last month.
Tens of thousands of forest dwellers were left stranded after rivers in the region faded into desert-like sandbanks.
Though water levels are now rising again, partly covering the apparently stone age etchings, local researchers photographed them before they began to disappear under the river's dark waters.
Archaeologists who have studied the photographs believe the art – which features images of faces and snakes – is another indication that thousands of years ago the Amazon was already home to large civilisations.
Eduardo Neves, president of the Brazilian Society of Archaeology and a leading Amazon scholar, said the etchings appeared to have been made between 3,000 and 7,000 years ago when water levels in the region were lower. The etchings were "further, undeniable evidence" that the region had been occupied by a significant number of ancient settlements and people.
"There has always been this idea that the Amazon was empty. The truth is that this hypothesis is not correct. In many parts of the Amazon we now have proof of settlements," he said, adding that the discovery was of great scientific importance.
Recent years have seen a growing number of archaeologists studying the Amazon, revising previous theories that the rainforest was too inhospitable to host a major civilisation.
"The conventional account of the Amazon basin is that it was inhabited by very small, often nomadic indigenous communities," said archaeologist Manuel Arroyo-Kalin, a research associate at University College London and Durham University familiar with the Manaus region.There was growing proof of "incredible pottery, large villages [and] roads going from one place to another" which "for a century or two" had been discarded by scholars.
With soy farmers, loggers and urban settlements advancing, cataloguing and preserving ancient Amazon sites had become a race against time.
"In the city of Manaus the amount of archaeology that has been destroyed is impressive," Arroyo-Kalin said.
Archaeologists are particularly concerned about the imminent inauguration of a 2.2-mile bridge across the Rio Negro connecting Manaus with Iranduba. The area is home to numerous archaeological sites, where ancient ceramics and burial urns have been found. "The bridge … will probably alter quite dramatically life on the other side of the Rio Negro … because [it] will put pressure on the land with urbanisation, and river fronts tend to be loaded with archaeological remains," Arroyo-Kalin said. "By changing the dynamic of how the region is being used … you will certainly start damaging archaeology."
Neves said he hoped the latest find would boost efforts to preserve the rainforest and its ancient secrets.
Drought brings rarities
Tide has raised engravings made for at least 7000 years found in rocks on the river Negro, in the 'area of the slabs'
Manaus, November 9, 2010
Among the finds is a stone taken by faces. Among the faces were highlights of an impish boy. Images can be seen better at night because the moon's reflection (Photo: Walter Calhoun / Free lancer)
A rare archaeological discovery was near the river Negro, in Manaus, thanks to extremely low water this year: rock carvings in the rocks located near the meeting of the waters. The site is known as "area of slabs" and belongs to the Union Among the drawings is a series of human faces etched in stone located on the riverside. It was also possible to identify geometric shapes, spirals and serpentine designs snakelike.
With the rise of the Negro River, the drawings begin to be covered by water. Earlier this week, the deputy manager of the Center for Environmental Studies and Projects of the Amazon (AERC), a division of Brazil Soka Gakkai Association, Akira Tanaka, recorded in the photo slots of various "faces" that had been discovered by a fisherman who passer-by.
On Monday, the area was already submerged, but another rock where the river level has not arrived yet still visible. The area of the slabs is located near a beach, in the back of the AERC, and next to the Belvedere of Embratel in the district Cologne Antônio Aleixo, Eastern Zone.
Biologist Elisa Wandel stressed that the discovery is unprecedented, because the parts most commonly found in the area are pottery and urns, objects that are part of the "Period Breakwater", which comprises the 9th century AD "These are inscriptions on stone, in the form of prints, not paintings. It can be a form of social communication. But that only archaeologists can tell, "he noted.
Yesterday, after reviewing photographs of the images sent by e-mail the story to criticize the President of the Brazilian Society of Archaeology, Eduardo Góes Neves, who lives in Sao Paulo, said it is "prints of great scientific dating of times further back, when the climate was somewhat drier in the region. "
In Nevis, the pictures were probably carved between the period between 7 and 3000 back. "Maybe it was also done during an exceptional drought like this year or at a time when the river was lower than now," he said.
Neves said that rock carvings found in the river Negro, in Manaus region, is somewhat rare, although common in other localities of the basin. He stressed the difficulty of doing research on stone carvings since these, unlike paintings, are no less organic debris.
Historian suggests research
The historian Andrew Bazzanela, former superintendent of the Institute of Historical and Artistic Heritage (Iphan), said "petroglyphs whose design resembles a geometric human face" as he prefers to call the pictures, remember those found in Itacoatiara, where there are many faces carved in stone, some in squares.
But he stressed that for any analysis it needs to be done further research.
"It's important to see that the inscription is in a shelter and not in the exposed rock, unlike the spirals and wavy lines also found in Ponta das Lajes. This has, of course, a meaning, a desire to perpetuate, "said Andrew Bazzanela.
Both the historian Eduardo Góes Neves reminded that research on the bank of Rio Negro have been developed by the archaeologist Raoni Valle. The report tried to interview Valle, but was informed that he is doing "field work" on the upper Rio Negro, incommunicado.
"The empirically Raoni did something in the region, raising the hypothesis that, in certain plates are permanently under water, the inscriptions could date up to 7000 years, when the river level was lower Negro," said Bazzanela.
For historians, it is necessary to research the symbols employed and a comparative iconographic survey. "However, the apparent relationship between Manaus and Itacoatiara that emerges through these petroglyphs, if confirmed, is another important step in building the history of the Amazonian territory."
Experts reveal brutal Viking massacre
9:30am Friday 5th November 2010
By Liam Sloan
VIKING skeletons buried beneath an Oxford college were the victims of brutal ethnic cleansing 1,000 years ago, archaeologists have discovered.
Experts were mystified when they discovered a mass grave beneath a quadrangle a St John’s College, St Giles, in 2008.
But, after two years of CSI-style detective work, they believe they can pinpoint the exact day in 1002 AD that Danish settlers were rounded up on the streets of Oxford and murdered, before being carted out of the city gates and dumped in a ditch.
Thames Valley Archaeological Services (TVAS) uncovered the remains of 34 to 38 young men in March 2008, during excavations for a new college building.
Bone experts realised they had been murdered as their skeletons were left with cracked skulls, stab wounds in their spines and pelvic bones, and there were signs of burning.
Five had been stabbed in the back, and one had been decapitated.
Tests dated them to between 960 and 1020 AD, and archaeologists first thought they were the remains of executed Saxon criminals.
But when the chemical composition of the bones was analysed, they revealed the men ate far more fish and shellfish than Anglo-Saxons, suggesting they were Viking settlers from Denmark.
Project leader Sean Wallis, of TVAS, believes they were killed on St Brice’s Day, November 13, 1002 AD, when King Aethelred the Unready ordered Englishmen across his kingdom to murder their Danish neighbours.
Documentary evidence shows Oxford residents rounded up the Danes and massacred them, burning down a wooden church where they fled for safety.
Mr Wallis said: “Obviously, we can never be 100 per cent definite, but everything points to these skeletons being the remains of the men murdered in the St Brice’s Day massacre.
“The level of the collagen in the bones suggests that they came from North West Europe, and their skeletons suggest they were big, muscular guys. I basically read this as ethnic cleansing.
“There were totally different circumstances 1,000 years ago, but basically the order went out that this particular race should be exterminated.
“It is the find of my career so far.”
Now some of the bones are being studied by forensic science students at Oxford and Cherwell Valley College, Oxpens Road.
Science lecturer Amy Dawson said: “The students are really excited to have something that is real and can be linked to a specific event.
“We can see the wounds inflicted at the point of death and prior to death.”
What will happen to the remains is not yet decided.
Found after 300 years, the scourge of the British navy
Wreck found off Plymouth is identified as feared French corsair
By Cahal Milmo
Friday, 12 November 2010
With 25 guns and a plunder-thirsty crew, La Marquise de Tourny was the scourge of the British merchant fleet some 260 years ago. For up to a decade, the French frigate terrorised English ships by seizing their cargoes and crew under a form of state-sanctioned piracy designed to cripple British trade.
Then, in the mid-18th century, the 460-ton vessel from Bordeaux, which seized three valuable cargo ships in a single year and distinguished itself by apparently never being captured by the English, disappeared without a trace. Nearly 300 years later, the fate of La Marquise and its crew can finally be revealed.
Wreckage from the frigate, including the remarkably well-preserved ship's bell carrying its name and launch date of 1744, has been found in the English Channel some 100 miles south of Plymouth by an American exploration company, suggesting that the feared privateer or "corsair" sank with the loss of all hands in a storm in notoriously treacherous waters off the Channel Islands.
The vessel is the first of its type to be found off British waters and one of only three known around the world, offering a unique insight into a frenetic phase of Anglo-French warfare when both countries set about beefing up their meagre navies in the mid-1700s by providing the captains of armed merchant vessels with "Letters of Marque" to take to the seas and capture enemy ships in revenge for attacks on other cargo convoys.
The result was an escalating war of commercial attrition during which these privately-owned English and French floating raiders fought each other to a stalemate by seizing more than 3,000 vessels each in a nine year period between 1739 and 1748 as both sides sought to choke off valuable trade with their colonies in America and the West Indies. The proceeds from the sale of a single cargo could be enough to make a corsair's crew rich for life.
Dr Sean Kingsley, a British marine archaeologist who has studied the remains of La Marquise de Tourny, told The Independent: "It is a rare symbol of the mid-18th century need to fuse business with warfare at a time when naval fleets were small. Many sea captains dreamed of finding enemy ships stuffed with treasure and becoming rich beyond their wildest dreams."
The wreck was first discovered by researchers working for Florida-based Odyssey Marine Exploration in 2008, but it has taken two years of painstaking archaeological detective work to conclusively establish the identity of La Marquise, not least because the site in the western end of the English Channel has been badly damaged by trawlers. Evidence such as the ship's hefty 52kg bell could now be offered on loan to French and British museums.
Odyssey, which last year announced it had also discovered nearby the remains of HMS Victory, the immediate predecessor to Admiral Nelson's flagship of the same name, has drawn criticism from some archaeologists for its excavation of wrecks and the selling of artefacts such as coins to recover its costs and fund future projects.
Odyssey argues that the site of La Marquise, where the wooden structure has been dispersed by fishing vessels and natural currents, shows that there is a race against time to examine such wrecks and retrieve whatever artefacts remain before they are destroyed.
Greg Stemm, the company's chief executive, said: "Unfortunately, this type of damage has been common to virtually every site we have discovered in the English Channel. It won't be long before this site will be completely erased from history, which makes it all the more important for the private sector to step in and help with projects."
The discovery of La Marquise nonetheless casts new light on privateering. Named after the wife of the Marquis de Tourny, the royal governor of Bordeaux credited with overseeing the French port's transformation into a colonial trade hub, the frigate-style ship would have combined marauding with delivering cargo between the Americas and French Channel ports.
Archaeologists believe that the vessel, which between 1746 and 1747 alone had captured four ships and possibly took many others, was distributing a perishable cargo such as coffee or sugar when it sank. It was held up as a fine example of a corsair built for speed whose design needed to be replicated in later vessels.