Last year, paleogeneticist Svante Paabo announced he was going to reconstruct the Neanderthal genome. Now, Paabo estimates he'll have a draft completed within two years.

When Paabo first announced the project, he drew a lot of skepticism since there were very few bits of mitochondrial DNA to work with. Things have taken a turn for the better since Paabo announced he found nuclear DNA in a 45,000 year old Croatian Neanderthal museum specimen and has been able to sequence a million base pairs of it.

The researchers� hope is to recover the entire sequence of the Neanderthal genome, but that will depend on which they can recover enough DNA. From sampling so far, no particular gaps in the sequence are apparent. �We are hitting all the chromosomes and getting good coverage,� Dr. Egholm said. If no single specimen yields a full sequence, the genome might be recovered by combining DNA from several individuals.

One of the most important results that researchers are hoping for is to discover, from a three-way comparison between chimp, human and Neanderthal DNA, which genes have made humans human. The chimp and human genomes differ at just 1 percent of the sites on their DNA. At 1 percent, Neanderthals resemble humans at 96 percent of the sites, to judge from the preliminary work, and chimps at 4 percent. Analysis of the DNA at the sites at which humans differ from the two other species will help understand the evolution of specifically human traits "and perhaps even aspects of cognitive function," Dr. Paabo said.

Both the New York Times and Discover Magazine mention the possibility of cloning a Neanderthal and possibly bringing the species back from extinction, but at this point, that sounds a bit far fetched. Yes, we've been able to clone a sheep and other animals, but it's been almost a matter of luck that these animals have survived through birth. Most don't. And given the ethical debate surrounding human cloning, I'd image that cloning a Neanderthal would receive the same backlash.

Source: Discover Magazine (Sept 2006), New York Times