Recovering the Neanderthal genome
February 19th 2009 06:20
In amazing new developments, the initial draft of the genome of a 38,000 year old Neanderthal has been completed (check out this article from Ewen Callaway in New Scientist for some more details). Scientists will be able to compare the genomes of modern Homo sapiens and the extinct human species H. neanderthalensis to see what sorts of changes have accrued since the two shared a common ancestor and what sorts of regions have likely been involved in developmental processes since the divergence. Also, it will give us more clues as to whether the two species engaged in any intermixing. Currently, signs are that they didn't do this to any significant extent if at all, but the newly sequenced genome will allow us to investigate this with considerably more certainty. I should also point out that I also said something apparently contradictory: I alluded to the possibility of two species intermixing. According to the biological species concept, a species is the most inclusive set of all potentially interbreeding individuals, so by that criteria, Neanderthals and H.sapiens should count as members of the same species if they could intermix and produce offspring. But, like so many things in nature, species are rather fluid and there are different ways to define them. Since species formation is typically a gradual process, a continuity must exist from varieties to sub-species to species proper (however defined). It is possible that we did interbreed and that the offspring were less viable but still left some genes behind in the population. Whatever the story, this is certainly a wonderful development and it will address some important questions about human evolution.
An excerpt from the article in New Scientist:
"Looming over the Neanderthal genome project has been the possibility of contamination from human handlers. Pääbo's team members perform much of their work while donning containment suits in clean rooms, and they have developed sequencing techniques to ferret out contamination.
"Despite these precautions, an earlier release by the same team of one million Neanderthal DNA letters in 2006 showed signs of human contamination.
"Those problems appear to be solved, says Rubin, citing the 2008 publication of a complete mitochondrial genome. "From that I'm expecting that this data's going to be largely Neanderthal."
An excerpt from the article in New Scientist:
"Looming over the Neanderthal genome project has been the possibility of contamination from human handlers. Pääbo's team members perform much of their work while donning containment suits in clean rooms, and they have developed sequencing techniques to ferret out contamination.
"Despite these precautions, an earlier release by the same team of one million Neanderthal DNA letters in 2006 showed signs of human contamination.
"Those problems appear to be solved, says Rubin, citing the 2008 publication of a complete mitochondrial genome. "From that I'm expecting that this data's going to be largely Neanderthal."
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