புதிய மனித வர்க்கம் கண்டுபிடிப்பு

நியண்டதரால் ( Neanderthal), சேபியன்ஸ் என்ற வரிசையில் இன்னுமொரு புது மனித கூர்ப்பு நிலைக்குரிய மனிதர்களின் DNA படிமக் கூறுகளை கண்டுபிடித்துள்ளனர்

New human' found in Siberian cave

A HOMINID that lived in southern Siberia some 40,000 years ago could be a new branch on the human family tree, a finding that would rewrite mankind's exodus from Africa and conquest of the Earth.

Scientists have announced they sequenced DNA from the bone fragment of a pinkie finger, possibly from a small child, found in a cave in the Alta Mountains.

The bone found in Denisova Cave was extricated in 2008 from a soil layer carbon-dated to between 30,000 to 48,000 years ago.

Teased from a cellular component called mitochondria, the genome was compared to the code of our extinct cousins the Neanderthals, of homo sapiens, the bonobo and chimpanzee.

The Siberian hominid, the investigation found, had some 400 genetic differences, which makes it a candidate for being a distinct species of homo, as the genus for humans and closely related primates is known.

It, us and the Neanderthals all shared a common ancestor who lived around a million years ago, according to the investigators.

"It's absolutely amazing," co-researcher Svante Paabo said.

"It's some new creature that's not been on our radar screen so far."

The study, published in the weekly journal Nature, is led by Johannes Krause of Germany's Max Planck Institute for Evolutionary Anthropology.

Members of the team previously sequenced most of the genome of the neanderthal.

If their findings are confirmed, much of the early tale of human settlement will have to be revamped.

Until just recently, it was also thought the only human species inhabiting the planet around 40,000 years ago were us and the neanderthals, who had only a little more time to run before they mysteriously disappeared.

The two-species picture dramatically changed in 2003, when "hobbit hominids" - metre-high humans with brains the size of a grapefruit - showed up in fossilised form on the Indonesian island of Flores.

If the "hobbits" and the Denisova human are accepted as a separate species that brings to four the tally of hominids who were all living at the same time and, in some cases, quite close to each other.

For instance, the Altai mountains have yielded evidence that homo sapiens made stone tools there, while neanderthals lived less than 100km from the Denisova Cave.

If so, what happened?

Did homo sapiens, bigger brained and smarter in communication, wipe out the other species?

Were the other species wiped out by some natural phenomenon or food crisis to which they could not adapt?

Or was there interbreeding, meaning that the extinct species are - in a purely DNA sense - living today through some genes bequeathed to all of us?

"All the theories are still open," University of Manchester specialist Terry Brown said.

"But the interesting thing is that they've just become more complex."

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