Un hueso del dedo de 30.000 años encontrado en una cueva en Siberia meridional perteneció a una chica joven que no era ni una humana premoderna ni un Neanderthal, sino que pertenecía a un grupo de parientes humanos primitivos, previamente desconocido, que pudieron haber vivido en muchas partes de Asia durante el Pleistoceno tardío. Aunque la evidencia fósil consiste en apenas un fragmento de hueso y un diente, el ADN extraido del hueso ha producido un bosquejo de secuencia genómica, permitiendo que los científicos extraigan sorprendentes conclusiones acerca de esta rama extinta del árbol genealógico humano, que recibe el nombre de "Denisovianos" por la cueva en la que se hallaron los fósiles.Al comparar la secuencia genómica Denisoviana con los genomas de Neanderthales y de seres humanos modernos, los investigadores concluyen que el Denisoviano era un grupo hermano de los Neanderthales y descendientes de la misma población ancestral que se había separado previamente de los antepasados de los actuales seres humanos. El estudio también encontró pruebas sorprendentes de la existencia de secuencias genéticas Denisovianas en melanesios actuales, sugiriendo que hubo entrecruzamiento entre Denisovianos y los antepasados de los melanesios, de la misma forma en que parece que los Neanderthales se cruzaron con los antepasados de todos los no-Africanos actuales.
Los Denisovianos parecen ser completamente diferentes genética y morfológicamente de los Neanderthales y de los seres humanos modernos. El diente, encontrado en la misma cueva que el hueso del dedo, muestra una morfología que se parece mucho más a la de viejos antepasados humanos, como Homo Habilis y Homo Erectus.
Entre los 28 coautores de la publicación hay científicos de Alemania, españa, China, Rusia, Canadá y Estados Unidos.
A 30,000-year-old finger bone found in a cave in southern Siberia came from a young girl who was neither an early modern human nor a Neanderthal, but belonged to a previously unknown group of human relatives who may have lived throughout much of Asia during the late Pleistocene epoch. Although the fossil evidence consists of just a bone fragment and one tooth, DNA extracted from the bone has yielded a draft genome sequence, enabling scientists to reach some startling conclusions about this extinct branch of the human family tree, called "Denisovans" after the cave where the fossils were found.
By comparing the Denisovan genome sequence with the genomes of Neanderthals and modern humans, the researchers determined that the Denisovans were a sister group to the Neanderthals, descended from the same ancestral population that had separated earlier from the ancestors of present-day humans. The study also found surprising evidence of Denisovan gene sequences in modern-day Melanesians, suggesting that there was interbreeding between Denisovans and the ancestors of Melanesians, just as Neanderthals appear to have interbred with the ancestors of all modern-day non-Africans.
The Denisovans appear to have been quite different both genetically and morphologically from Neanderthals and modern humans. The tooth found in the same cave as the finger bone shows a morphology that is distinct from Neanderthals and modern humans and resembles much older human ancestors, such as Homo habilis and Homo erectus.
The paper's 28 coauthors include scientists from Germany, Spain, China, Russia, Canada, and the United States.
Tomado de/ Taken from Science Daily
Resumen de la publicación/Abstract of the paper
Genetic history of an archaic hominin group from Denisova Cave in Siberia
Nature, 468, 1053–1060 (2010); doi:10.1038/nature09710
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
Abstract
Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population ‘Denisovans’ and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans
