GENETICS
Denisovan DNA in Living People
~46,000 years ago
Palaeolithic · Upper Palaeolithic · Last glacial
Populations of Asia and Oceania still carry Denisovan DNA, inherited from several encounters and useful today at high altitude.
The Denisovan inheritance designates the fraction of the genome of present-day Asian and Oceanian populations deriving from Denisovans. Its analysis establishes not one encounter but several: the archaic segments carried by Papuans fall into two groups whose mutual divergence matches that of populations separated for more than 350,000 years, which excludes an origin in a single Denisovan people, while East Asian populations carry a third. In Papuans this share reaches several per cent of the genome, and part of the contribution continues until near the end of the Pleistocene.
Why it matters
The inherited variants remain functional. In Tibetan populations, a version of the gene EPAS1, which is involved in the body's response to low oxygen, derives from Denisovan relatives: it shows the most marked signature of selection in their genome and regulates the quantity of haemoglobin produced at altitude. The case constitutes the best-documented example of an adaptive advantage inherited from another human lineage. Denisovans being known only from a few teeth, a finger bone and a mandible, most of what survives of them lies in the genomes of the living.
Dating & uncertainty
These episodes are not dated as fossils are: their trace is the length of archaic DNA segments in present-day genomes, which decreases at each generation and thus measures elapsed time. The models retain several successive contributions and at least three distinct Denisovan populations; the date given here corresponds to the principal contribution received by the ancestors of Papuans, gene flow east of the Wallace Line appearing to have continued until near the end of the Pleistocene.
Our species’ history as one day
20:29:423 h 30 min before midnight
if the 315,000 years of Homo sapiens were compressed into a single day