Did Neanderthals and early humans interbreed? Scientists have been asking themselves that question for decades, but now, as New Scientist reports, we may finally have the answer.
Paleogeneticist Svante Pääbo of the Max Planck Institute in Leipzig, Germany and his team claim this answer is "yes," because they've managed to sequence the Neanderthal genome using 38,000- and 44,000-year-old bones uncovered in Croatia. The New Scientist piece provides more details about the team's methodology, but their conclusions are pretty striking:
Any human whose ancestral group developed outside Africa has a little Neanderthal in them – between 1 and 4 per cent of their genome, Pääbo's team estimates. In other words, humans and Neanderthals had sex and had hybrid offspring. A small amount of that genetic mingling survives in "non-Africans" today: Neanderthals didn't live in Africa, which is why sub-Saharan African populations have no trace of Neanderthal DNA.
That said, the sequenced Neanderthal genome shows a vast, vast degree of similarity between the extinct species and modern Homo sapiens. New Scientist elaborates, "Pääbo's team found just 78 amino acid peculiarities – differences that change the shape and potentially the function of a protein – which all humans have in their genes but Neanderthals didn't." That's 78 peculiarities out of around 10 million amino acids.
Don't go looking for a tell-tale sign of Neanderthal genetic material in your friends, neighbors, and schoolyard bullies, either. The article says "no Neanderthal DNA sequences are consistently found in humans." Those of us without sub-Saharan ancestry may all have inherited different chunks of the Neanderthal genome, then.