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2010-05-07 Science & Technology

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Posted by tipper 2010-05-07 05:41|| || Front Page|| [3 views ] Top

#1 The link won't work, Tipper.

Posted by no mo uro 2010-05-07 06:01|| 2010-05-07 06:01|| Front Page Top

#2 Sorry, looks like you have to register.
The draft sequence of the Neanderthal genome, obtained from DNA fragments extracted from 40,000-year-old bones, shows that ancestors of modern Eurasians interbred to some extent with the Neanderthals they encountered as they moved out of Africa between 50,000 and 80,000 years ago.

The discovery, published in the journal Science, contradicts the previous view of most palaeontologists that there was no interbreeding between Neanderthals and modern humans.

A large international research effort, led by Svente Pääbo of the Max-Planck Institute for Evolutionary Anthropology in Leipzig, has succeeded in deciphering about 60 per cent of the Neanderthal genome.

The results show that 1 to 4 per cent of the DNA in people of non-African ancestry is from the Neanderthals, said Prof Pääbo. The Neanderthals are not totally extinct. In some of us a little bit of them lives on.

The researchers main raw material was pill-sized samples of powder extracted from three fossilised bones found in a Croatian cave. Other bones excavated in Spain, Germany and Russia contributed small amounts of DNA too.

The scientists used several gene sequencing technologies and powerful computer programs to piece together the degraded fragments of genuine Neanderthal DNA and extract them from all the bacterial and other contaminants that built up in the bones over tens of thousands of years.

The result is a scientific tour-de-force. Until six or seven years ago, I thought it would be impossible in my lifetime to sequence the Neanderthal genome, said Prof Pääbo.

Gregory Hannon, a geneticist at Cold Spring Harbour Lab in New York, called it a watershed event, a major historical achievement.

The interbreeding conclusion comes from comparing the Neanderthal genome with genomes of modern humans of European, Asian and African origins. To their surprise, the researchers found that everyone of Eurasian origin including people from East Asian and New Guinea where Neanderthals never lived carried a similar amount of Neanderthal DNA, while sub-Saharan Africans had none.

The likely solution to this puzzle is that the main interbreeding occurred in the Mediterranean region or Middle East when small bands of modern humans first moved out of Africa 50,000 to 80,000 years ago, before they dispersed across Eurasia. The two species may also have mated when they lived in close proximity in Europe until the Neanderthals died out about 30,000 years ago, but if so this later interbreeding left no impact on the modern human genome.

Racists may make something of the 1 4 per cent of Neanderthal DNA carried by modern Eurasians but not by Africans, Prof Pääbo said, but such arguments would not be valid.

His collaborator Ed Green of the University of California, Santa Cruz, said preliminary analysis suggested that nothing of functional significance came over from the Neanderthals. The [Neanderthal] signal is sparsely distributed across the genome, just a break crumbs clue of what happened in the past. If there was something that conferred a fitness advantage, we probably would have found it already by comparing human genomes.

Beyond proving that there was no biological barrier to Neanderthals mating productively with modern humans, the research shows that the two human species were genetically very similar in other ways. The astonishing implication of the work, said Prof Hannon, is that we are incredibly similar to Neanderthals at the level of the proteome, which is the full set of proteins that our genes encode.

Analysis of the genetic differences between Neanderthals and modern humans is just beginning. They include genes involved in cognitive development, skull and bone structure, energy metabolism, skin morphology and wound healing.

Prof Pääbo would not be drawn on whether the traditional view of Homo sapiens and Homo neanderthalensis as separate species, based largely on anatomical differences between their skeletons, remains valid. I would rather describe them as different forms of human and leave it to others to say whether they are different species, he said.

The Neanderthal genomes publication caps a fruitful few months of research into human origins. In March Prof Pääbos team published genetic evidence that another type of hominid neither Neanderthal nor modern human was living in Siberia 40,000 years ago. His lab is racing to sequence its genome.

Other groups have found important bones of much older hominid species in Africa, which might be our ancestors, including Ardipithecus living 4m years ago and Australopithecus sediba 2m years ago . But no traces of DNA remain on these fossils.

Posted by tipper 2010-05-07 06:54|| 2010-05-07 06:54|| Front Page Top

#3
I take it these researchers have met my Brother in law.

Posted by Parabellum 2010-05-07 08:06|| http://sidemeat.wordpress.com/ 2010-05-07 08:06|| Front Page Top

#4 ancestors of modern Eurasians interbred to some extent with the Neanderthals they encountered

even then, the ugly chicks were easy

Posted by Frank G 2010-05-07 08:37|| 2010-05-07 08:37|| Front Page Top

#5 Adding further credibility that man will mate with anything, including mud.

Posted by Procopius2k 2010-05-07 09:05|| 2010-05-07 09:05|| Front Page Top

#6 Beer goggles

Posted by Beavis 2010-05-07 09:47|| 2010-05-07 09:47|| Front Page Top

#7 I guess the Neanderthals had the study-bunny gene then?

Posted by rjschwarz 2010-05-07 10:18|| 2010-05-07 10:18|| Front Page Top

#8 Racists may make something of the 1-4 per cent of Neanderthal DNA carried by modern Eurasians but not by Africans, Prof Pääbo said, but such arguments would not be valid.

Quite the contrary. The discovery of human evil Eurasian inbreeding, [comely young female slaves and domestic help no doubt] simply reinforces the generally held negative connotations of the term Neanderthal. This revelation clearly explains African exceptionalism. I'm already beginning to feel guilt.

Posted by Besoeker 2010-05-07 11:12|| 2010-05-07 11:12|| Front Page Top

#9 Full "papers" may be read and/or downloaded here: http://www.sciencemag.org/cgi/content/full/328/5979/710 and http://www.sciencemag.org/cgi/content/full/328/5979/723

interesting reading.

Posted by ~dnt 2010-05-07 12:52|| 2010-05-07 12:52|| Front Page Top

#10 Well this at least explains the financial services sector.

Posted by bigjim-CA 2010-05-07 16:29|| 2010-05-07 16:29|| Front Page Top

#11 Adding further credibility that ~~man~~neanderthal will mate with anything, including mud.

There, fixed it for ya.

Posted by Thing From Snowy Mountain 2010-05-07 20:01|| 2010-05-07 20:01|| Front Page Top

#12 mating call: "look, I brought you a rock"

Posted by Frank G 2010-05-07 21:10|| 2010-05-07 21:10|| Front Page Top

#13 Explains my pronounced brow ridge. It also explains my above average cranial cavity capacity, resistance to mental disorders, my gentle nature, my affinity to arts.

I am (partially) Neanderthal and proud of it!

Posted by twobyfour 2010-05-07 21:48|| 2010-05-07 21:48|| Front Page Top

#14 Where does the urge to crack animals bone open for a marrow snack originate from?

Posted by Thrurt Barnsmell7160 2010-05-07 22:16|| 2010-05-07 22:16|| Front Page Top

#15 I'm guessing where lobster, steak, and free-range chicken weren't available? Think North Korea

Posted by Frank G 2010-05-07 22:37|| 2010-05-07 22:37|| Front Page Top

#16 Even jackels crack the bones for marrow. I imagine genus Homo had been doing that since we came down from the trees, long before sapiens and neaderthalus thought of evolving.

Posted by trailing wife 2010-05-07 23:16|| 2010-05-07 23:16|| Front Page Top

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