New evidence confirms suspicions that early modern humans, which left Africa some 300,000 to 750,000 years before Neanderthals, probably interbred with the physically stronger hominid species. The contact likely happened in the Middle East, the authors said, sometime after early modern humans left Africa 80,000 to 50,000 years ago.
Damian Labuda of the University of Montreal and the CHU Sainte-Justine Research Center and his colleagues analyzed a particular segment of the human X chromosome, one of the two sex chromosomes, known as dys44—an 8-kilobase intronic region that flanks the human dystrophin gene and has proved to be a useful marker for human evolutionary studies.Thanks to last year’s complete sequencing of the Neanderthal genome, the researchers could compare the genomes of more than 6,000 modern humans with the ancient hominid, and found similar intronic sequences on the Neanderthal X chromosome, as well as on the X of people from all continents except sub-Saharan Africa. The results are published in the July issue of Molecular Biology and Evolution.
“There is little doubt that this haplotype is present because of mating [of] our ancestors and Neanderthals,” Nick Patterson of the Broad Institute of MIT and Harvard University said in a press release. “This is a very nice result, and further analysis may help determine more details.”