DNA from dirt: Tracing ancient humans found in ‘empty’ caves

BERLIN — No bones? That’s because fossilized bones, currently the main source of ancient DNA, are scarce even at sites where circumstantial evidence points to a prehistoric human presence. And by analyzing damaged molecules they were able to separate ancient genetic material from any contamination left behind by modern visitors The researchers found evidence of 12 mammal families including extinct species such as woolly mammoth, woolly rhinoceros, cave bear and cave hyena. By further enriching the samples for human-like DNA, however, the scientists were able to detect genetic traces of Denisovans — a mysterious lineage of ancient humans first discovered in a cave in Siberia — and Neanderthals from samples taken at four sites. Crucially, one of the sites where they discovered Neanderthal DNA was a cave in Belgium, known as Trou Al’Wesse, where no human bones had ever been found, though stone artefacts and animal bones with cut marks strongly suggested people had visited it.