A multidisciplinary team which included participants from the Spanish National Research Council (CSIC) has discovered that Homo neanderthalensis and Homo sapiens crossbred over 100,000 years ago. This puts back the previously first-known case of a hybrid produced by the two species by 50,000 years. This earlier genetic exchange, which may have taken place in the Near East, has not been detected in European Neanderthals. The results of the work appear in the latest edition of 'Nature' magazine. A multidisciplinary team which included participants from the Spanish National Research Council (CSIC) has discovered that Homo neanderthalensis and Homo sapiens crossbred over 100,000 years ago. This puts back the previously first-known case of a hybrid produced by the two species by 50,000 years. This earlier genetic exchange, which may have taken place in the Near East, has not been detected in European Neanderthals. The results of the work appear in the latest edition of Nature magazine.

Analysed the genomes of a Neanderthal and a Siberian Denisovan, as well as the sequences of chromosome 21 of a Neanderthal found in the 'Sidrón' cave in Asturias, Northern Spain, and of another from Vindija, Croatia.

The CSIC researchers who took part in the study were Carles Lalueza-Fox (Institute of Evolutionary Biology) and Antonio Rosas (Spanish Natural Science Museum). Others who took part were the archaeologist, Marco de la Rasilla, along with other specialists in genomics, Tomás Marques-Bonet and Sergi Castellano, the latter being jointly responsible for the study.

Rosas explains that the work poses a brand new scenario. "Over 100,000 years ago, anatomically modern humans ventured out of Africa for the first time. These modern humans met and interbred with a group of Neanderthals, which later may have moved to the south of modern day Siberia, carrying the genes of H. sapiens."

What researchers have known since 2010, thanks to the study of the Neanderthal genome, is that around 50,000 years ago, following their migration from Africa, a group of modern humans- the predecessors of today's Europeans and Asians- interbred with Neanderthals. As a consequence of this gene flow, these non-African modern humans carry 2% genetic sequences from Neanderthals. In contrast, the Sub-Saharan modern human population, who never had any contact with Neanderthals, therefore do not carry this ancient gene (apart from very recent introgression).