Tuesday, February 24, 2009

Neaderthal Redux

Here is an interesting NY Times article on the state of research into the Neaderthal genome:
Scientists report that they have reconstructed the genome of Neanderthals, a human species that was driven to extinction some 30,000 years ago, probably by the first modern humans to enter Europe. ...

Possessing the Neanderthal genome raises the possibility of bringing Neanderthals back to life. Dr. George Church, a leading genome researcher at the Harvard Medical School, said Thursday that a Neanderthal could be brought to life with present technology for about $30 million. ...

He said at a news conference in Leipzig on Thursday that he now had retrieved usable DNA from six Neanderthals and analyzed 3.7 billion units of DNA. The Neanderthal genome, like that of modern humans, is 3.2 billion units in length. Because many units have been analyzed several times over, and many not at all, Dr. Pääbo can now see about 63 percent of the Neanderthal genome. He will continue to analyze it until he has accumulated the equivalent of 20 Neanderthal genomes, which will allow almost every unit to be accurately known. ...

Archaeologists have long debated whether Neanderthals could speak, and they have eagerly awaited Dr. Pääbo’s analysis of the Neanderthal FOXP2, a gene essential for language. Modern humans have two changes in FOXP2 that are not found in chimpanzees, and that presumably evolved to make speech possible. Dr. Pääbo said Neanderthals had the same two changes in their version of the FOXP2 gene. But many other genes are involved in language, so it is too early to say whether Neanderthals could speak. ...

When the full Neanderthal genome is in hand, could it be made to produce the living creature its information specifies? Ethical considerations aside, Dr. Pääbo said, Neanderthals could not be generated with existing technology. Dr. Church of Harvard disagreed. He said he would start with the human genome, which is highly similar to that of Neanderthals, and change the few DNA units required to convert it into the Neanderthal version.

This could be done, he said, by splitting the human genome into 30,000 chunks about 100,000 DNA units in length. Each chunk would be inserted into bacteria and converted to the Neanderthal equivalent by changing the few DNA units in which the two species differ. The changed lengths of DNA would then be reassembled into a full Neanderthal genome. To avoid ethical problems, this genome would be inserted not into a human cell but into a chimpanzee cell.

The chimp cell would be reprogrammed to embryonic state and used to generate, in a chimpanzee’s womb, a mutant chimp embryo that was a Neanderthal in many or most of its features.

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