Hominin bones recovered from Denisova Cave in Siberia, Russia, have provided the earliest securely dated evidence of the Denisovan lineage, and represent some of the oldest human fossils ever genetically sequenced.
Situated in the northwest Altai mountains, Denisova Cave offers the longest archaeological sequence in Eurasia, spanning from the Middle Pleistocene to the Holocene.
In 2010, genetic sequencing of a fossilised finger bone found at the site revealed the previously unknown archaic human species, the Denisovans, who diverged from a common ancestor shared with Neanderthals around 400,000 years ago.
According to a report recently published in Nature Ecology and Evolution, an international team of researchers, led by Assistant Professor Katerina Douka of the University of Vienna, used the biomolecular method known as collagen peptide fingerprinting or ‘ZooMS’ (Zooarchaeology by Mass Spectroscopy) to analyse ancient proteins and DNA in 3,791 non-diagnostic bone fragments extracted from the site’s oldest layers.
Five of the bone fragments were found to bear human collagen signatures and, of these, four had sufficient DNA for mitochondrial analysis. This study identified one bone as Neanderthal and the other three as Denisovan.
Dated to c. 200,000 years ago (or 217–187,000 years ago with 95% probability), these new fragments represent the oldest securely dated evidence of Denisovans.
Previously, the earliest known Denisovan fossil was discovered in 1984. It is estimated to be between 122-194,000 years old.
Two of the new fragments were also found to share an identical mitochondrial sequence, indicating that they either belong to a single individual or individuals related through the maternal line.
A wealth of lithics and faunal remains had previously been excavated from the same layer as the fossils. Now, with strong evidence of their association with Denisovans, the assemblage can offer more insight into the behavioural and environmental adaptions of this archaic hominin when it first appeared at the cave site.