It’s amazing what you find in old genes. DNA recovered from the skeleton of a man who lived in Ethiopia 4500 years ago has given archaeologists clues about humans’ migration back to Africa in antiquity.
Evidence from modern genomes suggests that there was a substantial movement of people from west Eurasia back to Africa – the cradle of humanity – about 3000 years ago. But with no ancient African DNA to study, important information on the nature of the migration has been missing.
Recovering DNA from ancient skeletons is usually very difficult, because the fragile molecule quickly breaks down, especially in warm climates. Ron Pinhasi from University College Dublin, Ireland, and his colleagues discovered that it was possible to get very high DNA yields from the petrous portion of the temporal bone, the densest bone in the mammalian body – as much as 500 times that from other bones.
Using this knowledge, the researchers have managed to extract and sequence DNA from the ancient skeleton of a man who lived 4500 years ago – dubbed Mota, after the cave in the southern Ethiopian highlands where he was buried. The cool, dry conditions inside the cave will have helped to make the DNA extraction successful.