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A study has shown that Neanderthal and Denisovan ancestors were related to superchaic hominins. During the middle Pleistocene, about 600,000 years ago, the homininsLarge-brained species first appeared in Europe and Asia, but their evolutionary history and species-to-species interactions have remained unclear.
A new study has provided information on the crosses between species and ends a discrepancy that existed on the moment in which the Neanderthal ancestors andDenisovansThey separated.
According to the fossils excavated in the Sima de los Huesos, inAtapuerca, and a model developed by the researchers in 2017, the separation occurred about 381,000 years ago.
“One of the fossils of the Sima de los Huesos was sequenced and it turned out to be clearly Neanderthal, so it lived after the separation between Neanderthals and Denisovans. However, that bone has now been dated at 600,000 years. This means that 381 thousand years was too early a date.”Explains Alan Rogers, an anthropologist at the University of Utah (USA).
The results obtained with the new model, published inScience Advances, show that the two human species separated about 600,000 years ago.
The ancestors of Neanderthals and Denisovans
Before, the ancestors of Neanderthals and Denisovans whom they have called 'neandersovans', They came across a large population ofsuper chaic hominins, about 700,000 years ago.
“Our new finding implies that two human populations interbred after a separation of more than a million years. Later, when the super-chaics crossed paths with the Denisovans, the separation time was even longer. These are basic data for speciation studies, ”says Rogers.
To solve this puzzle, the team set up eight models with different genetic combinations that may have resulted from early hominin reproduction.
To develop them, they included data from Neanderthals from the Altai Mountains in Siberia and from the Vindija Cave in Croatia, as well as from modern Europeans.
Between 20,000 and 50,000 super chaics
The job estimated the effective size of the superchaic population - those individuals who leave descendants - and found it to be surprisingly large,between 20,000 and 50,000 individuals.
"This may mean that there were many individuals or that there were several populations that were at least partially isolated from each other," he adds.
However, little else is known about these humans. According to the anthropologist, “this superchaic population could have beenHomo ancestor, Homo erectus, or some taxon not yet named. We do not know".
Furthermore, this study provides evidence that Humans expanded from Africa to Eurasia only three times: 1.9 million, 700,000 and 500,000 years ago.
A.R. Rogers; N.S. Harris; A.A. Achenbach. "Neanderthal-Denisovan ancestors interbred with a distantly related hominin."Science Advances (February 20, 2020).