News from the third branch of humanity, the Denisovans

A tiny fragment of a finger bone from Denisova cave in Siberia containing exceptionally well preserved DNA led in 2010, through the analysis of its genome, to the discovery of a previously unknown human population, the Denisovans, a sister-group of Neandertals. Denisovans have been documented living in the Middle and Upper Pleistocene (at least between 50,000 and 195,000 years ago) in southern Siberia and Tibet, but have left traces in the genomes of present-day populations in Melanesia and, to a lesser extent, in some populations in Asia. Yet, due to the scarcity of identified skeletal remains, almost nothing is known about their physical appearance. In the framework of an international, interdisciplinary collaboration coordinated by Eva-Maria Geigl, the Epigenome & Paleogenome group of the Institut Jacques Monod measured and photographed another fragment of the phalanx, analyzed its mitochondrial genome and demonstrated that it as the larger part of the famous phalanx that had yielded the first Denisovan genome. Paleoanthropologists from PACEA, University of Bordeaux, and from the Department of Anthropology, University of Toronto, Canada, reconstructed the image of the complete phalanx (Figure) and performed careful morphometric analyses of the measurements and pictures of the phalanx and comparison with finger phalanges of Neandertals and anatomically modern humans. This analysis shows that the finger phalanx of the Denisovan woman is close in shape to that of anatomically modern humans, in contrast to the molars and a recently identified mandible from Tibet. Thus, Denisovans seem to have mosaic characters that may challenge paleoanthropologists searching for Denisovan skeletal remains to better characterize morphologically this “third” branch of humanity.

Bibliography

Morphology of the Denisovan phalanx closer to modern humans than to Neandertals, E. Andrew Bennett, Isabelle Crevecoeur, Bence Viola, Anatoly P. Derevianko, Michael V. Shunkov, Thierry Grange, Bruno Maureille, and Eva-Maria Geigl, Science Advances in press

www.cnrs.fr/en/node/4037

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