• Trove of Neanderthal fossils found in Greek cave

    Katerina Harvati et al.

    A map of Greece (left) shows the approximate position of Kalamakia cave (right, shown with excavated sediments) and other sites with human remains in the Mani peninsula.

    By Charles Choi
    LiveScience

    A trove of Neanderthal fossils, including bones of children and adults, discovered in a cave in Greece hints the area may have been a key crossroad for ancient humans, researchers say.

    The timing of the fossils suggests Neanderthals and humans may have at least had the opportunity to interact, or cross paths, there, the researchers added.

    Neanderthals are the closest extinct relatives of modern humans, apparently even occasionally interbreeding with our ancestors. Neanderthals entered Europe before modern humans did, and may have lasted there until about 35,000 years ago, although recent findings have called this date into question.

    To learn more about the history of ancient humans, scientists have recently focused on Greece.

    "Greece lies directly on the most likely route of dispersals of early modern humans and earlier hominins into Europe from Africa via the Near East," paleoanthropologist Katerina Harvati at the University of Tübingen in Germany told LiveScience. "It also lies at the heart of one of the three Mediterranean peninsulae of Europe, which acted as refugia for plant and animal species, including human populations, during glacial times — that is, areas where species and populations were able to survive during the worst climatic deteriorations."

    "Until recently, very little was known about deep prehistory in Greece, chiefly because the archaeological research focus in the country has been on classical and other more recent periods," Harvati added.

    Harvati and colleagues from Greece and France analyzed remains from a site known as Kalamakia, a cave stretching about 65 feet (20 meters) deep into limestone cliffs on the western coast of the Mani Peninsula on the mainland of Greece. They excavated the cave over the course of 13 years. [Amazing Caves: Photos Reveal Earth's Innards]

    The archaeological deposits of the cave date back to between about 39,000 and 100,000 years ago to the Middle Paleolithic period. During the height of the ice age, the area still possessed a mild climate and supported a wide range of wildlife, including deer, wild boar, rabbits, elephants, weasels, foxes, wolves, leopards, bears, falcons, toads, vipers and tortoises.

    In the cave, the researchers found tools such as scrapers made of flint, quartz and seashells. The stone tools were all shaped, or knapped, in a way typical of Neanderthal artifacts.

    Now, the scientists reveal they discovered 14 specimens of child and adult human remains in the cave, including teeth, a small fragment of skull, a vertebra, and leg and foot bones with bite and gnaw marks on them. The teeth strongly appear to be Neanderthal, and judging by marks on the teeth, the ancient people apparently had a diet of meat and diverse plants.

    "Kalamakia, together with the single human tooth from the nearby cave site of Lakonis, are the first Neanderthal remains to be identified from Greece," Harvati said. The discoveries are "confirmation of a thriving and long-standing Neanderthal population in the region."

    These findings suggest "the fossil record from Greece potentially holds answers about the earliest dispersal of modern humans and earlier hominins into Europe, about possible late survival of Neanderthals and about one of the first instances where the two might have had the opportunity to interact," Harvati said.

    In the future, Harvati and her colleagues will conduct new fieldwork in other areas in Greece to address mysteries such as potential coexistence and interactions between Neanderthals and modern humans, the spread of modern and extinct humans into Europe and possible seafaring capabilities of ancient humans.

    "We look forward to exciting discoveries in the coming years," Harvati said.

    The scientists detailed their findings online March 13 in the Journal of Human Evolution.

    Follow us @livescience, Facebook and Google+. Original article on LiveScience.com.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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  • First love child of human, Neanderthal believed found

    Getty Images

    Neanderthals like the one depicted in this museum reconstruction died out tens of thousands of years ago.

    By Jennifer Viegas
    Discover News

    The skeletal remains of an individual living in northern Italy 40,000-30,000 years ago are believed to be that of a human/Neanderthal hybrid, according to a paper in PLoS ONE.

    If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.

    The present study focuses on the individual’s jaw, which was unearthed at a rock-shelter called Riparo di Mezzena in the Monti Lessini region of Italy. Both Neanderthals and modern humans inhabited Europe at the time.

    PHOTOS: Faces of Our Ancestors

    “From the morphology of the lower jaw, the face of the Mezzena individual would have looked somehow intermediate between classic Neanderthals, who had a rather receding lower jaw (no chin), and the modern humans, who present a projecting lower jaw with a strongly developed chin,” co-author Silvana Condemi, an anthropologist, told Discovery News.

    Condemi is the CNRS research director at the University of Ai-Marseille. She and her colleagues studied the remains via DNA analysis and 3-D imaging. They then compared those results with the same features from Homo sapiens.

    The genetic analysis shows that the individual’s mitochondrial DNA is Neanderthal. Since this DNA is transmitted from a mother to her child, the researchers conclude that it was a “female Neanderthal who mated with male Homo sapiens.”

    NEWS: Neanderthals Lacked Social Skills

    By the time modern humans arrived in the area, the Neanderthals had already established their own culture, Mousterian, which lasted some 200,000 years. Numerous flint tools, such as axes and spear points, have been associated with the Mousterian. The artifacts are typically found in rock shelters, such as the Riparo di Mezzena, and caves throughout Europe.

    The researchers found that, although the hybridization between the two hominid species likely took place, the Neanderthals continued to uphold their own cultural traditions.

    That's an intriguing clue, because it suggests that the two populations did not simply meet, mate and merge into a single group.

    NEWS: Neanderthals Died Out Earlier Than Thought 

    As Condemi and her colleagues wrote, the mandible supports the theory of "a slow process of replacement of Neanderthals by the invading modern human populations, as well as additional evidence of the upholding of the Neanderthals' cultural identity.”

    Prior fossil finds indicate that modern humans were living in a southern Italy cave as early as 45,000 years ago. Modern humans and Neanderthals therefore lived in roughly the same regions for thousands of years, but the new human arrivals, from the Neanderthal perspective, might not have been welcome, and for good reason. The research team hints that the modern humans may have raped female Neanderthals, bringing to mind modern cases of "ethnic cleansing."

    Ian Tattersall is one of the world’s leading experts on Neanderthals and the human fossil record. He is a paleoanthropologist and a curator emeritus at the American Museum of Natural History.

    Tattersall told Discovery News that the hypothesis, presented in the new paper, “is very intriguing and one that invites more research.”

    Neanderthal culture and purebred Neanderthals all died out 35,000-30,000 years ago.

  • Brain comparison suggests that Neanderthals lacked social skills

    Frank Franklin II / AP file

    A reconstructed Neanderthal skeleton, right, is on display near a modern human's skeleton, left, at the American Museum of Natural History in New York.

    By Jennifer Viegas
    Discovery News

    For ages, anthropologists have puzzled over Neanderthal and human brains, since they were the same size. If each species had comparable brain power, why did humans dominate?

    A comparison of Neanderthal and human brains has revealed it was a matter of allocation: Neanderthal brains focused more on vision and movement, leaving less room for cognition related to social networking.

    According to the study, published in the Proceedings of the Royal Society B, bigger-eyed and larger-bodied Neanderthals required more brain space devoted to the visual system and basic body functions, leaving less area for what co-author Robin Dunbar called "the smart part."

    He explained to Discovery News that this is "the part that is doing the creative thinking."

    Eye sockets measured
    Dunbar, a professor of evolutionary psychology at the University of Oxford, and colleagues Eiluned Pearce and Chris Stringer compared the skulls of 32 anatomically modern humans and 13 Neanderthals. The skulls date to 27,000 to 75,000 years ago. The researchers noticed that Neanderthals had significantly larger eye sockets.

    The researchers next used the known relationship between the height of the eye socket and the size of visual brain areas in living primates to estimate how much of each brain was dedicated to visual processing. Once differences in body and visual system size were taken into account, the researchers could then compare how much of the brain was left over for other types of cognition.

    It's clear that environmental differences affected the evolution of each species. The common ancestor of Neanderthals and Homo sapiens was Homo heidelbergensis. It had a bulkier body, as did the Neanderthals, but Homo heidelbergensis did not possess enlarged eyes.

    "The large eyes (of Neanderthals) are purely an adaptation to low light levels, and long dark nights at higher latitudes outside the tropics," Dunbar said.

    Flash interactive: Before and after humans

    Neanderthals also tended to be shorter than humans, which again was an adaptation to colder climates. Shorter stature reduces heat loss through the extremities. Modern Eskimos exhibit some of this adaptation.

    Neanderthals in Europe also "developed a very confrontational and dangerous style of hunting, and were very dependent on a heavy meat diet," Dunbar shared. "Modern humans (in Africa) developed the bow and arrow, as well as spear throwers, which allowed hunting at arms’ length and often focused on smaller prey."

    As for what happened to the Neanderthals, some researchers believe that they were simply absorbed into the modern human population. There is evidence that, as numerous humans migrated north into Europe, they interbred with Neanderthals.

    Social smarts
    Another theory, supported by this new study, is that Neanderthals went extinct because they were less capable of forming larger social networks. Pearce theorized that "smaller social groups might have made Neanderthals less able to cope with the difficulties of their harsh Eurasian environments because they would have had fewer friends to help them out in times of need."

    She continued, "Overall, differences in brain organization and social cognition may go a long way towards explaining why Neanderthals went extinct whereas modern humans survived."

    Dunbar further thinks that new diseases brought in by humans could have hurt Neanderthals. He said, "It was clear that, by the end, they were struggling to maintain a foothold in Ice Age Europe, having been squeezed down into the southern appendages of Europe (in places like Spain and Italy)."

    Clive Gamble, an expert on the archaeology of human origins and a professor at Southampton University, praised the new work. "This paper cracks a big problem in human evolution. Neanderthals had brains as big as ours, yet did not regularly produce the sorts of cultural stuff — art, ornamentation and complicated tools — that we take for granted ... Brains got bigger, but in different ways," Gamble said.

    "I've long argued for social differences between Neanderthals and ourselves," Gamble concluded. "It doesn't make us better than them and it doesn’t confirm the age-old prejudices about stupid, brutish Neanderthals. What it does do, quite literally, is make us see them with different eyes."

    More from Discovery News:

    Copyright 2013 Discovery Channel

  • African-American's Y chromosome sparks shift in evolutionary timetable

    University of Arizona

    A photomicrograph shows an X chromosome at left, alongside a shrunken Y chromosome. The Y chromosome is passed down exclusively from father to son and can serve as an indicator of male-line human diversity.

    By Alan Boyle, Science Editor, NBC News


    Scientists say an African-American male's odd genetic signature suggests that the human Y chromosome's lineage goes back further in time than they thought — perhaps due to interbreeding with other populations such as Neanderthals.

    "This really upsets a lot of ideas, but at the same time, it's understandable if we accept that human populations were structured in the past so that there were little pockets of diversity," said Michael Hammer, an evolutionary biologist at the University of Arizona who is one of the authors of a study published in the American Journal of Human Genetics.

    The study focuses on the analysis of a DNA sample that was obtained from an African-American living in South Carolina and submitted to the Genographic Project, a National Geographic effort aimed at mapping human origins and migration. The funny thing about this sample is that it didn't match up with any of the previously known genetic signatures for the Y chromosome, which is passed down from father to son.

    "Nobody expected to find anything like this," Hammer said in a news release.

    A team led by Fernando Mendez, a researcher in Hammer's lab, analyzed more than 240,000 DNA base pairs on the African-American's Y chromosome. A comparison of the differences between the mystery genetic signature and previously known signatures led the team to conclude that the most recent common ancestor for the entire group lived about 338,000 years ago.

    That goes further back than the fossil record goes for anatomically modern humans, Hammer said. "The fossil record speaks to 195,000 years or 200,000 years," he said. It also goes further back than the previous date for the most recent common ancestor based on Y-chromosome analysis, which is in the range of 142,000 years.

    The researchers followed up on their discovery by searching through a genetic database for African populations, and turned up 11 men from western Cameroon who had virtually the same genetic signature.

    Hammer said there could be two explanations for the previously unidentified Y-chromosome type: Either the genetic heritage of anatomically correct humans really does go back much further than what's reflected in the fossil record — or other populations, such as Neanderthals or the more recently identified Denisovans, interbred with modern humans. Anthropologists refer to that pattern of divergence followed by renewed interbreeding as introgression.

    The results are "more consistent with introgression of an odd lineage," Hammer told NBC News. Over the past few years, scientists have been coming around to the view that such interbreeding did take place early in the history of our species. Recent analysis of Neanderthal and Denisovan DNA has indicated that a part of their genetic heritage survives in modern-day humans.

    Melissa Wilson Sayres, a geneticist at the University of California at Berkeley who played no role in Hammer's study, said the new findings were "exciting" because they pointed to a Y-chromosome lineage more ancient than any others. "They just happened to come across this one Y chromosome that was hidden for so long, and it's very likely that there are more hidden Y chromosomes around the world," she told NBC News.

    She said one of the biggest debates in the study of human genetics has to do with how to match mutation rates with time scales — and she expects this latest study to add to the debate. For example, some might continue to argue that the most recent common ancestor lived more recently than 338,000 years ago. "It will still be the oldest Y-chromosome heritage that we have, but I can foresee that some people might disagree with that specific age," she said.

    More about our genetic origins:

    In addition to Hammer and Mendez, the authors of "An African American Paternal Lineage Adds an Extremely Ancient Root to the Human Y Chromosome Phylogenetic Tree" include Thomas Krahn, Bonnie Schrack, Astrid-Maria Krahn, Krishna R. Veeramah, August E. Woerner, Forka Leypey Mathew Fomine, Neil Bradman, Mark G. Thomas and Tatiana M. Karafet. The authors acknowledged Jacqueline Johnson and her male cousins, the descendants of Albert Perry (South Carolina) and participating Family Tree DNA customers.

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

  • Neanderthals died out earlier than thought, new testing finds

    Neanderthal Museum (Mettmann, Germany)

    The last Neanderthals had passed by southern Iberia quite earlier than previously thought — about 45,000 years ago and not 30,000 years ago as it has been estimated until recently. The new finding casts doubt on the theory that modern humans and Neanderthals coexisted in Iberia during the Upper Pleistocene.

    By Charles Choi
    LiveScience

    Neanderthals may have died out earlier than before thought, researchers say.

    These findings hint that Neanderthals did not coexist with modern humans as long as previously suggested, investigators added.

    Modern humans once shared the planet with now-departed human lineages, including the Neanderthals, our closest known extinct relatives. However, there has been heated debate over just how much time and interaction, or interbreeding, Neanderthals had with modern humans.

    To help solve the mystery, an international team of researchers investigated 215 bones previously excavated from 11 sites in southern Iberia, in an area known as Spain today. Neanderthals entered Europe before modern humans did, and prior research had suggested the last of the Neanderthals held out in southern Iberia until about 35,000 years ago, potentially sharing the region with modern humans for thousands of years.

    Their data suggest that modern humans and Neanderthals may have actually lived in the area at completely different times, never crossing paths there at all. Even so, these findings do not call into question whether modern humans and Neanderthals once had sex — the findings simply indicate this interbreeding must have occurred earlier, before modern humans entered Europe.

    "The genetic evidence for interbreeding — 1 to 4 percent Neanderthal DNA in present-day modern humans — suggests that interbreeding probably occurred before the period we are looking at in the Levant, the region around Israel and Syria, when modern humans first migrated out of Africa," researcher Rachel Wood, an archaeologist and radiocarbon specialist at Australian National University in Canberra, told LiveScience.

    Dating bones
    Scientists discover the ages of artifacts and fossils using a variety of techniques. For instance, radiocarbon dating determines the age of biological remains based on the ratio between the carbon isotopes (atoms of the same element with different numbers of neutrons) carbon-12 and carbon-14 it holds — this proportion changes as radioactive carbon-14 breaks down while stable carbon-12 does not. Researchers can also look at the layers of soil and rock in which objects are found — if these layers were not disturbed over the years, then objects in the same layer should be the same age.

    The investigators concentrated on collagen, the part of bone most suited for radiocarbon dating. Only eight of these bones from two sites in Spain — Zafarraya Cave and Jarama VI — had enough collagen for analysis. [ Image Gallery: Our Closest Human Ancestor ]

    One bone, which came from a wild goat, was found in Zafarraya Cave in a similar layer as Neanderthal fossils. The bone was previously estimated as 33,300 years in age. However, using an ultrafiltration technique that cleansed the bone of modern carbon impurities that can give inaccurate younger dates, they found the bone was more than 46,700 years old.

    "Our work suggests that at present, it is unlikely that Neanderthals survived any later in this area than they did elsewhere in mainland Europe," said researcher Thomas Higham at the University of Oxford in England.

    The most surprising thing "was the enormous difference that the ultrafiltration dating made to the chronologies of the sites we looked at," Wood said. "At other sites in Europe, we have seen that this improved method of dating bone makes a difference, making old bones older. However, we do not normally see such consistently large differences. This is probably because the preservation of the organic materials — bone and charcoal — that are normally radiocarbon dated is really poor in warm climates like southern Spain."

    Analysis of the remaining samples revealed they were at least 10,000 years older than previously estimated. Instead, they were close to or more than 50,000 years old, the upper limit for radiocarbon dating.

    When Neanderthals died out
    "Our results cast doubt on a hypothesis that has been broadly accepted since the early 1990s — that the last place for surviving Neanderthals was in the southern Iberian Peninsula," Wood said. "Much of the evidence that has supported this idea is based on a series of radiocarbon dates, which cluster at around 35,000 years ago. Our results call all of these results into question."

    These findings suggest modern humans and Neanderthals might not have interacted in this area. In northern Iberia, about 150 miles (250 kilometers) north of Jarama VI, past research suggested modern humans were only present starting about 42,000 years ago. These new findings hint that modern humans and Neanderthals did not coexist for millennia as before thought, and did not live side-by-side. [ 10 Mysteries of the First Humans ]

    "The results of our study suggest that there are major problems with the dating of the last Neanderthals in modern-day Spain," Higham said. "We now have to look very cautiously at the model of late Neanderthal survival in southern Iberia and focus our efforts on more rigorous dating programs."

    One site, Cueva Antón in Spain, did seem as young as previously thought. However, it remains uncertain whether the artifacts there are linked with Neanderthals — they may belong to modern humans.

    The researchers caution they are not definitely saying that there were no Neanderthals in southern Iberia after 42,000 years ago. "What we have is a gap where we have no reliable radiocarbon dates. There might have been Neanderthals or modern humans or both or neither," Wood said. Also, "there are several circumstances which could have obscured later interbreeding events in Europe, so it is not possible to say, for example, that at one time there was not more Neanderthal DNA in Europeans."

    The scientists detailed their findings online Monday in the journal Proceedings of the National Academy of Sciences.

    Follow LiveScience on Twitter @livescience. We're also on Facebook   and   Google+.

  • Help wanted: 'Adventurous' woman to give birth to ... a Neanderthal baby?

    By Alan Boyle, NBC News

    Getty Images

    Neanderthals like the one depicted in this museum reconstruction died out tens of thousands of years ago, but geneticist George Church says it may be possible to bring their DNA back into the gene pool.

    Pioneering Harvard geneticist George Church suggests that the day is coming when we'll want to reverse-engineer the Neanderthal genome and pass the now-extinct creatures' advantages to our own progeny. All that's needed would be an "extremely adventurous female human" to serve as a surrogate mother.

    During an interview with the German magazine Der Spiegel, Church was asked whether a Neanderthal baby would be born in his lifetime. "That depends on a hell of a lot of things," the 58-year-old replied, "but I think so."

    Is he serious?

    Well, Church is serious about the promise of synthetic biology, which involves tinkering with the chemical components of DNA to add artificial twists to the code of life. Microbes could be tweaked to produce better biofuels or harness solar power. White blood cells could be rejiggered to fight cancer or other diseases, using a tamed form of the HIV virus. And extinct species could be brought back to life through a combination of cloning and genetic engineering.

    The species-resurrection scenario would involve inserting the reconstructed nuclear genetic material from the extinct creature into the living egg of a closely related present-day species, sparking the cell into dividing, and then implanting the resulting embryo into the womb of a female from the present-day species. It's been discussed in the context of using elephants to bring back mammoths, or chicken hens to bring back dinosaurs. 

    Technically speaking, the progeny wouldn't be a mammoth or a dinosaur, but rather an elephant or chicken exhibiting the genetic traits of their long-departed relatives. A similar technique could be applied using Neanderthal DNA: Chunks of reconstructed genetic code could be used to reprogram human cells and produce increasingly Neanderthal-like stem cells.

    "If we do that often enough, then we would generate a stem cell line that would get closer and closer to the corresponding sequence of the Neanderthal," Church told Der Spiegel. "We developed the semi-automated procedure required to do that in my lab. Finally, we assemble all the chunks in a human stem cell, which would enable you to finally create a Neanderthal clone."

    In the current political, ethical and technological climate, there's no way this scenario could come to pass. Researchers are closing in on a high-quality Neanderthal genome, but they're not quite there yet. The Russian and Korean scientists behind the mammoth-cloning project say they're years away from doing their experiment. And the idea of getting humans involved in cloning experiments is still the stuff of science fiction.

    However, Church's point is that the Neanderthal genetic code may be so valuable that the hurdles will be worth overcoming.

    "Neanderthals might think differently than we do," he told Der Spiegel. "We know that they had a larger cranial size. They could even be more intelligent than us. When the time comes to deal with an epidemic or getting off the planet or whatever, it's conceivable that their way of thinking could be beneficial."

    Theoretically, it might be possible to create a whole population of neo-Neanderthals and see how they differ from the usual breed of Homo sapiens, Church said.

    "Curiosity may be part of it, but it's not the most important driving force," Church said. "The main goal is to increase diversity. The one thing that is bad for society is low diversity. This is true for culture or evolution, for species and also for whole societies. If you become a monoculture, you are at great risk of perishing. Therefore the re-creation of Neanderthals would be mainly a question of societal risk avoidance."

    Does the idea of Neanderthal surrogate motherhood sound sensible when he puts it that way? Or does it still sound like a science-fiction nightmare? Feel free to weigh in with your comments below.

    More about the DNA frontier:

    Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.