Nov. 15, 2006 — Early humans and Neanderthals, our closest and ill-fated evolutionary cousins, shared the same habitat for hundreds of thousands of years, but engaged in little or no inter-species hanky-panky, scientists have said.
Two pathbreaking studies published Wednesday in the journals Nature and Science also confirmed earlier estimates that the two related branches of the hominid family tree went their separate genetic ways some 500,000 years ago.
Using distinct techniques of DNA sequencing — which analyzes genetic fragments recovered, in this case, from Neanderthal remains — the coordinated scientific papers also predicted that the complete Neanderthal genome would be pieced together within two years.
Not long ago the prospect of sequencing the entire genome of an extinct organism was regarded by many specialists as simply impossible.
The demise of Neanderthals some 30,000 years ago is often blamed on smarter and more adaptable Homo sapiens, but there is still no scientific consensus on the exact cause of extinction.
The two studies, one headed by Edward M. Rubins and the other by Svante Paabo, arrived at similar conclusions using cutting-edge but different scientific tools.
A commentary in Nature introducing both papers suggested they were the "most significant contributions" published in the field since the discovery of Neanderthals 150 years ago.
The team of U.S., German and Croat researchers led by Paabo, Director of the Genetics Department at the Max Planck Institute for Evolutionary Anthropology in Leipzig, used a technique called pyrosequencing to analyze one million base pairs of Neanderthal DNA, removing impurities and matching the fragmentary genetic sequences against the template of human chromosomes.
"Our finding that the Neanderthal and human genomes are at least 99.5 percent identical led us to develop and successfully implement a targeted method for recovering specific ancient DNA sequences," the authors wrote.
