Anatomically modern humans overlapped and mated with Neanderthals

Recently, genomic studies have shown that Neanderthals interbred with modern humans, and that non-Africans today are the products of this mixture.

Neanderthals come from Homo heidelbergensis, who left Africa (more or less) half million years ago, and developed in Europe and Asia. Homo sapiens left Africa much more recently, 100-120 thousand years ago.

That´s the reason why it´s believed that the mixture happened 50-60 thousand years ago in Middle East. There anatomically modern humans overlapped and mated with Neanderthals such that non-African humans inherit ~1 to 3% of their genomes from Neandertal ancestors.

Regions that harbour a high frequency of Neanderthal alleles are enriched for genes affecting keratin filaments, suggesting that Neanderthal alleles may have helped modern humans to adapt to non-African environments. Neanderthals were used to a cold, dark and escarce enviroment, while Homo sapiens were adapted to a warm and abundant one.

It were indentified multiple Neanderthal-derived alleles that confer risk for disease, suggesting that Neanderthal alleles continue to shape human biology. An unexpected finding was that regions with reduced Neanderthal ancestry are enriched in genes, implying selection to remove genetic material derived from Neanderthals.

This researchs prove definetly that modern human had more than one DNA source, which made the genoma we have today.

Free interpretation of how a modern human and neanderthal would look like

Sources:

• http://evoanth.wordpress.com/2013/03/28/when-did-humans-leave-africa/
• http://www.nature.com/nature/journal/v507/n7492/full/nature12961.html
• http://news.discovery.com/human/evolution/how-neanderthal-dna-changed-humans-140129.htm