Neanderthal nookie notion nixed

Will Parker
14 August 2012
http://www.scienceagogo.com/news/20120713195113data_trunc_sys.shtml

Hybridization, the idea that modern humans and Neanderthals once interbred is probably wrong, say researchers at the University of Cambridge who suggest that a common ancestry better explains the DNA we share with Neanderthals. The new work, that details an alternative explanation for the 1-4 percent shared Eurasian and Neanderthal DNA, appears in the journal PNAS.

Central to the new research is the fact that Africans have almost none of the Neanderthal genome. In previous studies this was explained by suggesting hybridization occurred after modern humans exited Africa and later bred with the Neanderthals who already inhabited Europe.

Study leader, Dr Andrea Manica, explained that Neanderthals and modern humans likely once shared a common ancestor who spanned Africa and Europe about half a million years ago. "Just as there are very different populations across Europe today, populations of that common ancestor would not have been completely mixed across continents, but rather closer populations would have been more genetically similar to each other than populations further apart," she said.

Then, about 300-350,000 years ago, the European range and the African range became separated. The European range evolved into Neanderthal, the African range eventually turned into modern humans. However, explains Manica, because the populations within each continent were not freely mixing, the DNA of the modern human population in Africa that were ancestrally closer to Europe would have retained more of the ancestral DNA (specifically, genetic variants) that is also shared with Neanderthals.

Exploring this idea, Manica's team created a model to determine whether the differences in genetic similarities with Neanderthal among modern human populations, which had been attributed to hybridization, could be down to the proximity of modern humans in northern Africa (who would have later gone on to populate Europe) to Neanderthals.

By examining the different genetic makeup among modern human populations, the scientists' model was able to infer how much genetic similarity there would have been between distinct populations within a continent. The researchers then simulated a large number of populations representing Africa and Eurasia over the last half a million years, and estimated how much similarity would be expected between a random Neanderthal individual and modern humans in Africa and Eurasia.

Manica concluded that when modern humans expanded out of Africa 60-70,000 years ago, they would have brought out that additional genetic similarity with them, making Europeans and Asians more similar to Neanderthals than Africans are on average - undermining the theory that hybridization, and not common ancestry, explained these differences.

"Based on common ancestry and geographic differences among populations within each continent, we would predict out of Africa populations to be more similar to Neanderthals than their African counterparts - exactly the patterns that were observed when the Neanderthal genome was sequenced; but this pattern was attributed to hybridization. Our work shows clearly that the patterns currently seen in the Neanderthal genome are not exceptional, and are in line with our expectations of what we would see without hybridization. Hopefully, everyone will become more cautious before invoking hybridization, and start taking into account that ancient populations differed from each other probably as much as modern populations do," she noted.

Neanderthals Mated With Humans Outside of Africa

Katie Scott July 18, 2011
http://www.wired.com/wiredscience/2011/07/neanderthal-human-mating/

It has been a long held belief that our human ancestors came into contact with Neanderthals, and recent findings not only confirm this, but also suggest exactly how “close” this contact was.

Damian Labuda of the University of Montreal’s Department of Pediatrics and the CHU Sainte-Justine Research Center and team have found part of the human X chromosome comes from the Neanderthals and is found only in people outside of Africa.

In a paper published in the July issue of the journal Molecular Biology and Evolution, the geneticists write: “We provide evidence of a notable presence (nine percent overall) of a Neanderthal-derived X chromosome segment among all contemporary human populations outside Africa”. The team analyzed 6,092 X-chromosomes “from all inhabited continents”. Their discovery confirms earlier hypotheses that early modern man and Neanderthals mixed and mated.

The ancestors of the Neanderthals are believed to have left Africa between 400,000 to 800,000 years ago. However, by 30,000 years BC, they had disappeared. The ancestors of modern man left Africa between 80,000 and 50,000 years BC, suggesting that there was a definite crossover between the two.

Discovery News adds: “The team believes most, if not all, of the interbreeding took place in the Middle East, while modern humans were migrating out of Africa and spreading to other regions.”

This finding comes nearly ten years after Labuda and team identified a piece of DNA in the human X chromosome (called haplotype) that seemed different. A release detailing the findings explains: “When the genome of Neanderthals was sequenced in 2010, they quickly compared to 6,000 chromosomes from across the world with the haplotype of the Neanderthal. The sequence of the Neanderthal man was found in people of all continents, including Australia, but with the exception of sub-Saharan Africa.”

David Reich, a geneticist at Harvard Medical School, and one of the researchers involved in the project of deciphering the genome of Neanderthals says: “Labuda and his colleagues were the first to identify in non-African genetic variation may come from an archaic population. At the time, they have identified without access to the genome sequence of the Neanderthal. Today, in light of the Neanderthal genome sequence, it is clear that they were absolutely right.”

Can fingers point to sex habits?

http://cosmiclog.msnbc.msn.com/_news/2010/11/02/5397036-can-fingers-point-to-sex-habits
Can fingers point to sex habits?
11-2-10

Researchers measured the length of fossilized fingers from Ardipithecus and other ancestors on humanity's family tree, then compared them with modern-day species in hopes of figuring out how aggressive and promiscuous long-gone species might have been.

Alan Boyle writes: The oldest-known species on humanity's family tree was built to be pushy and promiscuous, while another long-ago ancestor known as Lucy was lovey-dovey. Early humans and Neanderthals were more competitive than we are. At least those are the conclusions that researchers reached after sizing up the fingers of extinct and present-day primates.

The study, published in the Proceedings of the Royal Society B, draws upon a famous and controversial indicator of social behavior: the comparative length of the index finger and the ring finger, also known as the 2D:4D ratio.

If the ring finger is longer than the index finger, that's supposed to be correlated with higher prenatal exposure to androgens -- resulting in a higher proclivity for aggressiveness and promiscuity. The finger-length ratio also has been linked to sexual orientation as well as sporting prowess and musical ability.

(Did you just look at your fingers?)

Emma Nelson, an archaeologist from the University of Liverpool, extended the finger-length ratio study to a wide range of species. She and her colleagues measured bones from modern-day species such as gorillas, chimps, orangutans and the white-handed gibbon. They also looked at fossil bones or previously recorded measurements from extinct hominids ranging from Neanderthals (which co-existed with humans until about 30,000 years ago) to Australopithecus afarensis (Lucy's species, going back 3.1 million years) and Ardipithecus ramidus (the oldest human-linked fossil species, going back 4.4 million years).

Nelson argues that comparing the finger-length ratios of extinct and present-day species is a valid technique for making an indirect assessment of our long-gone ancestors' social behavior.

"It is believed that prenatal androgens affect the genes responsible for the development of fingers, toes and the reproductive system," she explained in a news release. "We have recently shown that promiscuous primate species have low index-to-ring finger ratios, while monogamous species have high ratios. We used this information to estimate the social behavior of extinct apes and hominins."

Nelson previewed her findings a year ago at the Society of Vertebrate Paleontology's annual meeting, where she talked about naughty Neanderthals and monogamous australopiths. The newly published paper draws upon additional samples, including the finger lengths for Ardipithecus, or "Ardi." So here are the numbers:

•Modern humans averaged a 0.957 index-to-ring finger ratio, and were considered to be on the line between a "pair-bonded," or monogamous, species and a middle-of-the-road species.

•Chimps, gorillas and orangutans had index-to-ring ratios in the 0.90 to 0.92 range, and were classified as "non-pair-bonded," or promiscuous.

•An early modern human from Israel's Qafzeh Cave, thought to be about 95,000 years old, had an index-to-ring ratio of 0.935. Based on that statistic, the researchers surmised this individual would be more promiscuous than modern humans.

•The finger bones from five Neanderthals yielded a 0.928 ratio, associated with even greater competitiveness and promiscuity. Ardipithecus' bones took it up another notch, to 0.899. Two even older primate ancestors, Hispanopithecus and Pierolapithecus, had ratios of 0.848 and 0.908, which means they would have been tough to live with as well.

•On the other end of the spectrum, the monogamous gibbons had a 1.009 ratio ... and the australopith sample came in with a ratio higher than that of modern-day humans (0.979). The implication, then, is that australopiths were monogamous.
The big question is whether there's anything substantial to this analysis. Nelson acknowledged that the fossil record was sparse, and that more fossils were needed for study, but she insisted that "this method could prove to be an exciting new way of understanding how our social behavior has evolved."

Other researchers have tried to make guesses about the social behavior of extinct hominid species by looking at sexual dimorphism -- that is, the differences between the male and the female of a species. If the males were significantly larger, the assumption is that they were built to have their way with many females in a promiscuous social setting. This has generated a fair amount of debate, particularly when it comes to assumptions about australopiths.

Nelson and her colleagues suggest that the finger-length ratio could serve as an additional tool for making more educated guesses about ancient social behavior.

"Social behaviors are notoriously difficult to identify in the fossil record," one of Nelson's fellow authors, the University of Oxford's Susanne Shultz, said in the news release. "Developing novel approaches, such as finger ratios, can help inform the current debate surrounding the social systems of the earliest human ancestors."

When this research first came to light last year, University of Wisconsin anthropologist John Hawks cautioned against reading too much into fossilized fingers. He said the index-to-ring ratio "may be correlated with mating system in primates, but that doesn't mean it's a good predictor of mating system. ... As fossil hominins go, I wouldn't expect the story to go any further -- there just aren't many hands, so there's never going to be a significantly predictive result."

Are Redheads Descended From Neanderthals?

http://www.disinfo.com/2010/10/are-redheads-descended-from-neanderthals/
Are Redheads Descended From Neanderthals?
Posted by majestic on October 13, 2010

In Entangled, Graham Hancock’s debut novel, an essential part of the story involves the so-called “Neanderthal Enigma,” a raging academic debate over what caused Homo neanderthalensis to die out some 35,000 years ago. Hancock’s Neanderthals, called the “Uglies,” play an important role in Entangled. They are depicted as gentle, sensitive, telepathic, creative: They did not make cave paintings but they did use makeup.

Shocking new scientific research suggests that Hancock’s depiction of Neanderthals may be far closer to the truth than even he may have thought. Jennifer Viegas reports for Discovery News via MSNBC:

Neanderthals are often depicted as brutish club wielders, but a new book suggests Neanderthals had a sensitive side, displaying “a deep seated sense of compassion.”

The findings, also published in the journal Time & Mind, are part of a larger study charting how empathy and other related feelings evolved in early humans.

Researchers Penny Spikins, Andy Needham and Holly Rutherford from the University of York Archaeology Department examined archaeological evidence for the way emotions began to emerge in our ancestors six million years ago and then developed through more recent times.

Based on fossils, artifacts and other evidence, the scientists propose a four stage model for the development of human compassion...


But that’s not all! Marc Kaufman reports in the Washington Post that there’s a wholesale re-evaluation of how Neanderthals relate to us, saying that these often disparaged humans are actually “more like our brothers and sisters than even our cousins.”

And apparently “recent finds suggest quite a few in central Europe were handsome redheads.” So if there’s a ginger in your life...

The Washington Post story is well worth reading if you are interested in the topic — there are many more fascinating items about Neanderthals.

Posted in: Ancient History, Antropology, Biology, Bizarre, Entangled, Evolution, Graham Hancock, Humans, Neanderthals

Scientists unravel Neanderthal genome

http://www.guardian.co.uk/science/2009/feb/12/neaderthal-genome

Scientists unravel Neanderthal genome
Extraordinary feat will shed light on what it means to be human
Ian Sample, Chicago
Thursday 12 February 2009

Scientists have unravelled the genetic make-up of the Neanderthal, the long-faced, barrel-chested relative of modern humans.

Anthropologists analysed more than a billion fragments of ancient DNA plucked from three Croatian fossils to reconstruct a first draft of the Neanderthal genome.

The extraordinary feat gives scientists an unprecedented opportunity to clarify the evolutionary relationship between humans and Neanderthals that may ultimately shed light on the great mystery of how we became the most formidable species on the planet.

Neanderthals were the closest relatives of modern living humans. They lived in Europe and Asia until they became extinct around 30,000 years ago. The reason they died out is not clear, but likely factors are dramatic swings in the climate that affected the availability of food, and competition with early humans.

By comparing the genomes of modern humans with Neanderthals and chimps, scientists hope to unravel the genetic differences that define what it is to be human.

The Neanderthal genome was built up from strands of DNA, most of which came from a 38,000-year-old fossilised leg bone unearthed in a cave in Vindija, Croatia. Other material came from older remains dating back 70,000 years. Together, the fragments make up more than 60% of the Neanderthal genome.

Svante Pääbo, who led the project at the Max Planck Institute for Evolutionary Biology in Leipzig, Germany, said the team would spend the rest of the year analysing the DNA. They will focus on genes linked to modern human evolution, such as FOXP2, which is involved in speech and language.

The draft genome was announced at the American Association for the Advancement of Science meeting in Chicago.

Two years ago, the same group used the ancient DNA to pinpoint the moment, about 500,000 years ago, when modern humans split from Neanderthals.

The analysis should clear up once and for all the ongoing debate as to whether Neanderthals and modern humans continued to mate with each other after separating along the path of evolution.

Remains of Neanderthals dating back to 400,000 years ago suggest they were proficient at crafting basic tools and weapons and buried their dead. The last Neanderthals died out shortly after Homo sapiens migrated to Europe and settled.

Neanderthals were stocky and well-adapted to a cold climate, with brains that were on average larger than those of modern humans. Some fossil evidence suggests they were occasionally cannibalistic, though they more commonly hunted large animals including horses and mammoths.

Chatty Cave Men? Me Neanderthal, Talk Good

http://www.livescience.com/health/071018-neanderthal-language.html

Chatty Cave Men? Me Neanderthal, Talk Good
By Charles Q. Choi, Special to LiveScience
18 October 2007

Neanderthals might have spoken just like humans do now, new genetic findings suggest.

Neanderthals are humanity's closest extinct relatives. Since their discovery more than 150 years ago, researchers have found out they could make tools just like our ancestors could, but whether Neanderthals also had advanced language, rather than mere grunts and groans, has remained hotly debated.

To learn more, scientists investigated DNA from Neanderthal bones collected from a cave in northern Spain, concentrating on a gene, FOXP2, which is to date the only one known to play a role in speech and language. People with an abnormal copy of this gene have speech and language problems.

Genes similar to FOXP2 are found throughout the genomes of the animal kingdom, from fish to alligators to songbirds. The molecule that human FOXP2 generates differs from chimpanzee FOXP2's by just two amino acids, the building blocks of proteins.

Past research suggests the gene's modern human variant evolved fewer than 200,000 years ago. Now scientists find the Neanderthal FOXP2 gene is identical to ours. The ancestors of Neanderthals diverged from ours roughly 300,000 years ago, according to the latest thinking. Some studies have suggested that the two species might have intermingled after that, however.

"It is possible that Neanderthals spoke just like we do," paleogeneticist Johannes Krause of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told LiveScience.

"Of course many genes are involved in language," cautioned Krause, the new study's lead researcher. As scientists discover more of such genes, these will have to be examined in Neanderthals as well, he said.

Krause noted that some might suggest that interbreeding or "gene flow" (aka sex) between modern humans and Neanderthals led to us having FOXP2 in common. "However, we see no evidence for gene flow in the Y chromosome sequences," he said. Instead, the modern human and Neanderthal Y chromosomes are substantially different genetically.

Krause and his colleagues detailed their findings online Oct. 18 in the journal Current Biology.