Some of the human X chromosome originates from Neanderthals and is found exclusively in people outside Africa, according to an international team of researchers led by Damian Labuda of the Department of Pediatrics at the University of Montreal and the CHU Sainte-Justine Research Center. The research was published in the July issue of Molecular Biology and Evolution.
"This confirms recent findings suggesting that the two populations interbred," says Dr. Labuda. His team places the timing of such intimate contacts and/or family ties early on, probably at the crossroads of the Middle East.
Neanderthals, whose ancestors left Africa about 400,000 to 800,000 years ago, evolved in what is now mainly France, Spain, Germany and Russia, and are thought to have lived until about 30,000 years ago. Meanwhile, early modern humans left Africa about 80,000 to 50,000 years ago. The question on everyone's mind has always been whether the physically stronger Neanderthals, who possessed the gene for language and may have played the flute, were a separate species or could have interbred with modern humans. The answer is yes, the two lived in close association.
"In addition, because our methods were totally independent of Neanderthal material, we can also conclude that previous results were not influenced by contaminating artifacts," adds Dr. Labuda.
Dr. Labuda and his team almost a decade ago had identified a piece of DNA (called a haplotype) in the human X chromosome that seemed different and whose origins they questioned. When the Neanderthal genome was sequenced in 2010, they quickly compared 6000 chromosomes from all parts of the world to the Neanderthal haplotype. The Neanderthal sequence was present in peoples across all continents, except for sub-Saharan Africa, and including Australia.
http://www.eurekalert.org/pub_releases/2011-07/uom-grc071411.php
