As modern humans migrated out of the Middle East after encountering Neanderthals, and dispersed across the globe, they carried Neanderthal DNA with them. The research team concluded that 2 percent of the genomes of present-day humans living from Europe to Asia and as far into the Pacific Ocean as Papua New Guinea was inherited from Neanderthals. The team did not find traces of Neanderthal DNA in the two present-day humans from Africa. It is not known, however, whether a more systematic sampling of African populations will reveal the presence of Neanderthal DNA in some indigenous Africans.
"The data suggests that the genes flowed from Neanderthal to modern humans," Dr. Mullikin said. "That had to have occurred at least once during the 20,000 to 30,000 years, in which modern humans and Neanderthal both lived on the Eurasian continent." The researchers have not yet detected any signs that DNA from modern humans can be found in the Neanderthal genome.
Previous studies, such as the International HapMap Project, which created a comprehensive catalog of human genetic variation, examined common genetic variation in populations across the globe, and concluded that average genetic variation between a person in Asia, Europe or Africa was essentially identical. The current study raises the possibility that Europeans and Asians, who include Neanderthal DNA, may be slightly more distinct from Africans than previously appreciated a difference at the DNA sequence level that could not be seen with the resolution of the HapMap.
"These are preliminary data based on a very limited number of samples, so it is not clear how widely applicable these findings are to all populations," said Vence L. Bonham, Jr., J.D., senior advisor to the NHGRI Director on Societal Implications of Genomics. "The findings do not change our basic understanding that humans originated in Africa and dispersed around the world in a migration out of that continent."
|Contact: Larry Thompson|
NIH/National Human Genome Research Institute