Ancient DNA from our human ancestors: Genetic secrets of the Neanderthals

It has been known for decades from fossil evidence that after modern humans left Africa ~60,000 years ago, they began to share the territory of Neanderthals in Europe and Central Asia, with both species coexisting together. However, our understanding of human evolution was fundamentally changed after the genome sequencing of ancient DNA from Neanderthal fossils, which revealed that modern humans outside of Africa all harbor around 2% of Neanderthal DNA. This results from a single human + Neanderthal population mixture event ~50,000 years ago in the early Out of Africa human population, which left these footprints of Neanderthal DNA in our own modern human genomes. Therefore, humans today are the largest collection of Neanderthal DNA available. We can reconstruct Neanderthal genomes by mining these small Neanderthal DNA fragments from the genomes of modern humans and piecing them back together like a puzzle. Sophie Joseph, Molecular & Cell Biology