We are not only a little Neanderthals, but also a little Denisovans
The nuclear genome of a hominin from Denisova Cave has been decoded
Dmitry Safin, CompulentaSpecialists from the USA, Germany, Canada and Russia have completed the decoding of the nuclear genome of an unknown hominin, a fragment of whose finger phalanx was discovered in 2008 in the Denisova Cave by employees of the Institute of Archaeology and Ethnography SB RAS.
Archaeologists estimated the age of the unremarkable specimen at 30-48 thousand years. In the spring of the outgoing year, we already reported on the decoding of the corresponding mitochondrial genome; then it was found that the mtDNA lines of modern humans, Neanderthals and new hominins, which the authors call Denisovans, diverged about a million years ago - long before man separated from Neanderthals.
The analysis of the nuclear genome with a volume of about 3 billion "letters" allowed us to clarify these data. Now researchers say that hominin DNA is more like Neanderthal than human, and the separation of the DNA sequences of Neanderthals and Denisovans occurred about 640,000 years ago.
The researchers compared the received version of the decoding with the known genomes of representatives of 53 modern populations and in one case found traces of interspecific crossing. According to the authors, the Melanesians inhabiting the islands to the northeast of Australia received from the Denisovans from four to six percent of the genetic material. If we take into account that Neanderthals also left their mark on the genomes of modern humans, the total contribution of Pleistocene populations will increase to about 8%.
The new work also presents a description of a tooth found in Denisova Cave. Unlike the unremarkable fragment of the phalanx, it has unusually large dimensions and resembles (but does not copy) the molars of Homo erectus and Homo habilis. The mitochondrial genomes compiled from the results of the study of the phalanx and tooth were similar. Despite this, Denisovans do not have the status of a separate species or subspecies.
The full version of the report is published in the journal Nature: Genetic history of an archaic hominin group from Denisova Cave in Siberia.
Prepared based on the materials of Nature News: Fossil genome reveals ancestral link.
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23.12.2010