Thursday, December 23, 2010

Does Homo Erectus Walk Among Us?

There is a lot of discussion about a recent Nature article which looks at DNA from an ancient group of humans found in Denisova Cave in Russian Siberia.
Fossils found in the Russian republic of Altai belong to a previously unknown branch of human development.

Researchers at the University of California who were conducting the study found that the remains belong to a little girl, who died 30,000 years ago.

According to experts, she was not of the Neanderthal species, as a tooth similar to the structure Homo Erectus teeth was discovered. _Ruvr.ru

Some modern-day people carry Denisovan genes. Through genetic comparisons Pääbo’s team found that some people from Melanesia — an assemblage of islands off Australia’s east coast, including New Guinea — share 4 to 6 percent of their genomes with the Denisovans. This probably indicates that the Denisovans interbred with anatomically modern humans despite the split between our lineages over a million years ago. _Wired

ImageSource
The most significant finding in the paper is the demonstration that some living humans trace significant fraction of their ancestry to the population represented by the Denisova genome. As in the case of Neanderthals, different human populations show significantly different levels of similarity to the Denisova sequence. For Neanderthals, the similarities indicated between one and four percent Neanderthal ancestry for living people outside of Africa. In the case of the Denisova sequence, the greatest similarities are with living people in Melanesia – in this paper, represented by genome samples from Papua New Guinea and Bougainville. The similarities are consistent with approximately 4% contribution of a Denisova-like population to the ancestry of these living Melanesians.

The paper estimates that together, the Denisova and Neanderthal-derived genes account for 8% of the ancestry of these living people. _JohnHawks
...the evidence now suggests that an ancestral group of early humans left Africa up to 400,000 years ago and diverged, with one branch heading to Europe and becoming the Neanderthals and a second moving east and becoming Denisovans.

When modern humans left Africa - some 80,000 years ago - they came into contact with first the Neanderthals before another group interbred with Denisovans, the traces of which now exist in Melanesia. _Telegraph
Wired

John Hawks' Denisova FAQ

Interesting discussion of implications for anthropology and the "Out of Africa" thesis

Greg Cochran suggests in comments that Denisovans are likely an Asian Homo Erectus.

Erectus Walks Among Us -- a free-wheeling, highly speculative and imaginative look at an alternative anthropological theory contesting "Out of Africa" in a most strenuous manner.  Unintentionally humorous in many ways.  Not Safe for Work

Apparently, due to the Denisovan findings and the recent Neandertal genome findings, a lot of anthropological data will need to be re-sorted and reclassified. It does not help matters when issues of "political correctness" which are so rampant in the field of "cultural anthropology" are allowed to intrude upon the far more scientific branch of "physical anthropology."

Unfortunately, modern science is so corrupted by political constraints and politicised funding and publishing, that an objective study of many areas of science is practically prohibited. Time may erode the stranglehold of political correctness on science, eventually.

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