The ancient mysteries of Denisov cave have been discovered
New research reveals a profound history of archaic people in southern Siberia
Two new surveys cast light when two groups of archaic people (hominins)-Neanderthals and their enigmatic relatives, the Denisov cave Denisova in Russia, the only location in the world that is known to be occupied by both groups of hominins and by modern people in different times.
For the first time, the studies set a time line when the Denis and Neanderthals were present at the site and the environmental conditions they faced before they disappeared. The denizens, which were recently discovered, lived simultaneously with Neanderthals and modern humans who swam the Earth, but were genetically different from the two.
Findings published in Nature on January 31, 2019, are the result of many years of detailed investigation by a multidisciplinary team of researchers from Russia, Australia, Canada, Germany and the United Kingdom.
New research shows that hominins have almost uninterruptedly occupied the site through a relatively hot and cold time in the last 300,000 years, leaving back stone tools and other artifacts in the caves. Fossils and DNA traces from Denisovani have been found at least 200,000 to 50,000 years, and those of the Neanderthals between 200,000 and 100,000 years.
In 2018, the bone fragment from the cave brought the gene to the daughter of the parents Neanderthal and Denisovan – the first direct evidence of crossing between two archaic hominine groups. New studies reveal that this girl lived about 100,000 years ago.
The Denisov cave is located at the foot of the Altai Mountains in Siberia and has been excavated for 40 years by archaeologists from the Institute of Archeology and Ethnography (Siberian Branch of the Russian Academy of Sciences) in Novosibirsk.
The site first appeared in the world in 2010, with the publication of the genome derived from a finger of a previously unknown type of hominine, called Denisovani. Following further discoveries about the genetic history of the Denisovans and the Altaic Neanderthals, on the basis of the analysis of the several fragmentary hominins remains.
So far, reliable dates for hominine fossils found from cave deposits have remained elusive, as well as dates for DNA, artifacts, and animals and plants are derived from sediments.
Fifty years of radioactive clusters and more than 100 optical age dates support the new chronology of the Denisova cave, as well as the minimum age for the bone fragment of mixed neanderthal / Denis origin from uranium-series.
One of the studies, led by Professor Zenobia Jacobs, the Australian Research Council (ARC) Future Partner with the University of Wollongong in Australia, included optically giving cavity sediments, most of which are too old to give a radioactive node. Optical dating measures the time when the grains of quartz or feldspar in the sediment were last exposed to light.
Another study, led by Dr. Katerina Duuka of the Institute of Human History Science Max Planck, Germany, receives a radioactive cardboard from bone, tooth, and coal fragments that are corrected from the upper layers of the site, and a developed statistical model for integrating all dating information for the cave.
"This new timeline for the Denisova cave provides a timeline for the richness of data generated by our Russian colleagues about the archaeological and ecological history of the cave during the last three glacial-interglacial cycles," said Professor Jacobs.
"We had to invent some new methods to find the deepest and oldest sites and build a robust chronology of the sediments in the Denisova Cave," said Associate Professor Bo Lee, geochronologist and ARC Future Fellow at the University of Wollongong.
To determine the probable ages of archaic hominine fossils, a statistical model was developed at the University of Oxford in the United Kingdom.
The model combined optical, radioactive cardboard and uranium series with adults with information on the stratigraphy of deposits and genetic ages for Desyosan and Neanderthal fossils relative to each other – the latter based on the number of substitutions in the mitochondrial DNA sequences that were analyzed in Max Planck Institute of Evolutionary Anthropology in Germany.
Dr Duka said that improved age estimates for hominine fossils obtained using the new statistical model "incorporate all available evidence of these small and isolated fossils that can easily be displaced after sedimentation."
Modern humans were present in other parts of Asia 50,000 years ago, but the nature of all meetings between them and the Denizens remains open to speculation in the absence of any fossil or genetic traces of contemporary people in the place.
"For the same reason, another open question is whether the Denisovites or modern people have made the oldest bones and personal ornaments [tooth pendants] found in the cave, "says Professor Tom Hajdam (University of Oxford), co-author of the study on the radioactive node and the statistical modeling study.
"With direct dates from 43,000 to 49,000 years ago, they are the earliest such artifacts known throughout northern Eurasia."
Professor Richard Burt Roberts, co-author of both papers and director of the Center for Excellence in Australian Biodiversity and Heritage, based at the University of Wollongong, said that studies have expanded our understanding of the ancient inhabitants of the cave, much to learn.
"While these new studies have raised the veil of some of the mysteries of the Denis Cave, it remains to answer other interesting questions with further research and future discoveries," he said.
The research was supported by the Russian Science Foundation, the Russian Foundation for Basic Research, the state task of the Ministry of Education and Science of the Russian Federation, the Australian Research Council, the European Research Council, the Max Planck Society, the Royal Society, and the Social Sciences Research Council social sciences of Canada.
"The Time of the Archaic Hominic Occupation of the Denisova Cave in the Southern Siberia" by Zenobia Jacobs, Bo Lee, et al. (DOI: 10.1038 / s41586-018-0843-2); and "Age estimates for hominine fossils and the beginning of the Upper Paleolithic in the Cave Denisova" by Katerina Duka and others (DOI: 10.1038 / s41586-018-0870-z) are published in the January 31, 2019 edition of Nature.
Provided by the University of Wollongong
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