尼尔德人和现代人类曾经通婚！

[yolanda]

是这个月的轰动新闻。德国科学家通过测定尼尔德人基因序列， 发现和France, China and Papua New Guinea的现代人有共同序列，但是与现代非洲人序列没有共同处 。。。

From The Times
May 7, 2010
Neanderthal gene found in human DNA of people living out of Africa
Mark Henderson, Science Editor

They have been extinct for 30,000 years, but a small part of the Neanderthals lives on in the DNA of every person with ancestors outside Africa.

The genetic code of Neanderthal Man has revealed that Homo sapiens mated with our closest evolutionary relatives soon after migrating out of Africa, leaving traces that can still be detected in human DNA.

A comparison of the genomes of the two human species has shown that between 1 and 4 per cent of the DNA of modern non-Africans has a Neanderthal origin, while no Neanderthal genes can be detected in Africans today. This indicates that the first modern humans to leave the continent must have interbred with Neanderthals they encountered, probably in the Middle East. Their descendants went on to populate the other continents.

“Those of us who live outside Africa carry a little Neanderthal DNA,” said Svante Pääbo, of the Max Planck Institute in Leipzig, Germany, who led the research. “What we find is that Neanderthals are slightly more similar in their genome to people outside Africa, no matter whether they live in Europe, Asia or Papua New Guinea. This shows that there has been gene flow between Neanderthals and populations ancestral to humans,” he added.

The findings, published in the journal Science, settle a long-running controversy over whether Neanderthals bred with modern humans or made any lasting contribution to the human gene pool.

Previous research had found no evidence of such gene flow. This had led many scientists to believe that Homo sapiens displaced other human species as it spread around the world.

Human genomes from France, China and Papua New Guinea showed Neanderthal signatures, but not those from West and Southern Africa.

“How these peoples would have interacted culturally is not something we can speculate on in any meaningful way,” said Richard Green, of the University of California, Santa Cruz, a member of the study team. “But ... it is fascinating to think how that may have happened.”

Comparisons between the human and Neanderthal genome will reveal genetic changes that occurred after the evolutionary divide between the two species, some of which may underlie unique capabilities of Homo sapiens such as complex thought, language and art.

Already more than 200 parts of the human genome that show signals of rapid evolution since the split from Neanderthals, which include several genes involved in brain development, have been found.

Another interesting gene that has evolved is RUNX2 which, when mutated, causes skeletal abnormalities typical of Neanderthals, such as a bell-shaped rib cage.

Ewan Birney, of the European Bioinformatics Institute, near Cambridge, said that the work would provide many more insights into humanity’s genetic peculiarities. “This gives us a new way to investigate what makes humans human,” he said. Dr Pääbo added: “It’s cool to think that some of us have a little Neanderthal DNA in us, but, for me, the opportunity to search for evidence of positive selection that happened shortly after the two species separated is probably the most fascinating aspect of this project.”

The Neanderthal genome covers 60 per cent of the species’ full genetic code and was pieced together from DNA from six skeletons from four sites: Vindija Cave in Croatia, El Sidrón in Spain, Mezmaiskaya in Russia and Feldhofer in the Neander Valley in Germany, where the original specimens that gave the species its name were found.

New methods of sequencing DNA that allows ancient genetic material to be read, although it is highly degraded, enabled the research to be conducted. It was also necessary to avoid introducing modern human DNA that would have ruined the samples.

Professor Chris Stringer, head of the human origins group at the Natural History Museum, said: “The Neanderthal genome strongly suggests that many of us outside of Africa have some Neanderthal inheritance. Any functional significance ... remains to be determined, but that will certainly be a focus for the next stages of this fascinating research.”

[yijun]

本来么，只要不存在物种隔离，两个人群相遇，总是会有两情相悦的事情发生的，而并不总是打打杀杀吧。
同理，东亚大陆的古人类种群，也多半会跟中东迁徙过来的人群通婚的。
提个问题，“between 1 and 4 per cent of the DNA of modern non-Africans has a Neanderthal origin, ”是怎么计量的？照这个数量级，那么现在这些有尼尔德人（一般中译为尼安德特人）血缘的人们，与非洲人的DNA的差异至少大于4%，而每一个人群内部的差异度，至少小于1%，这样的DNA普查数据库已经很庞大了吧？按照这个定义标准来做人群分布图的话，有这样的结果了吗？

[yolanda]

不太懂统计耶; 好像比较的基点是不一样的， 而且有许多假定； 文中好像说不同的研究结果数据很不一样。 我只是听说文中用的测序平台借机宣传他们的产品， 公司股票都涨了一些 （illumina)！
原文可免费阅读：
http://www.sciencemag.org/cgi/content/f ... 8/5979/710

[yijun]

呵呵，那我只好去啃原文了：）有问题再问。

[yijun]

[img]http://www.sciencemag.org/content/vol328/issue5979/images/medium/328_710_F1.gif[/img]
用来取DNA的骨头，以及欧洲的化石采集点。