In early 2010, Svante Pääbo, director of the Genetics Department of the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany), and an international team of researchers demonstrated that the mitochondrial DNA of a 30,000-year-old finger bone found at Denisova Cave in southern Siberia, Russia, contained an unusual genetic sequence that suggested they were dealing with a previously unknown ancient form of hominin.

The latest analyses of the nuclear genome of this extinct hominin preserved in Denisova Cave and the morphology of a tooth from the same specimen now suggest a history different from other hominin groups for the Denisovan population. On 23 December, the Nature journal published this important scientific discovery that will help us understand the origins of human evolution.

Tomàs Marqués-Bonet, a researcher at the joint UPF-CSIC Institute for Evolutionary Biology (Institut de Biologia Evolutiva, IBE), is the only Spanish researcher to have joined the international team that characterized the genome of this evolutionary brother of the Neanderthals.

His contribution to the analyses was to study the genome's variant structural regions, which, according to Marquès-Bonet, "are typically difficult to characterize and are related with certain human illnesses that indicate, at the same time, that the genome of the Denisovans, at least for some regions, is more archaic than that of other hominins, since it shares certain characteristics with the chimpanzee genome".

The Denisovans contributed to the genome of Melanesians

Based on their genome sequence, the Denisovans were apparently a hominin group sharing common origins with the ancient Neanderthals, but who later evolved differently and had a different history. In contrast to the Neanderthals, the Denisovans did not contribute to today's Euro-Asian genes. However, they seem to be more closely related to the modern population of Melanesia -a region of Oceania including the island of New Guinea-, which suggests they must have mixed with the ancestors of the Melanesians. In fact, the Melanesians bear 4-6% of the genetic material of the extinct Denisovans.

The fact that the Denisovans were discovered in southern Siberia but that there are traces of their genetic material in modern human populations of Southeast Asia suggests that this group of hominins may have occupied a large part of Asia during the late Pleistocene (some 50,000 years ago).

The genome analysis indicates the remains belonged to a 6-7 year-old girl

After analyzing the nuclear DNA of the remains found, researchers have concluded that the Denisova finger bone was that of a girl of 6 to 7 years of age who belonged to a group of hominins sharing a common genetic origin with the Neanderthals. At the same time, the results show a series of characteristics suggesting a different demographic history for this hominin group.

The analysis of a tooth of the same specimen displays a morphology different to that of both Neanderthals and modern humans; in fact, it is much closer to that of ancient hominins such as Homo erectus or Homo habilis. In combination with the Neanderthal genome sequence published by the same team in early 2010, the Denisovan genome suggests a complex image of genetic interactions between our ancestors and other ancient hominin groups living at that time.

Reference:

David Reich, Richard E. Green, Martin Kircher, Johannes Krause, Nick Patterson, Eric Y. Durand, Bence Viola, Adrian W. Briggs, Udo Stenzel, Philip L. F. Johnson, Tomislav Maricic, Jeffrey M. Good, Tomas Marques-Bonet, Can Alkan, Qiaomei Fu, Swapan Mallick, Heng Li, Matthias Meyer, Evan E. Eichler, Mark Stoneking, Michael Richards, Sahra Talamo, Michael V. Shunkov, Anatoli P. Derevianko, Jean-Jacques Hublin, Janet Kelso, Montgomery Slatkin & Svante Pääbo, (2010), "Genetic history of an archaic hominin group from Denisova Cave in Siberia", Nature, 23 December 2010. 

Press clippings:  El País 23/12/2010, El Periódico de Cataluña