Scientists try to unravel secrets of Denisovans, of male relatives

For a long time, Homo sapiens coexisted with at least two other human species - belonging to the same genus. One of them were Neanderthals, extensively studied

In a cave icy Siberia, 30m above the Anuy Creek, died a little girl of 7 years. Dark skin, she had eyes and brown hair. It is feeding the bear meat, wild boar and lynx, animals typical of this inhospitable region where Russia is ahead of Kazakhstan and Mongolia. His remains remained there long. Until, in 2008, an archaeologist found a sliver of the girl's finger bone inside the cave, called Denisova because of a legendary hermit, Denis, who lived there in the 18th century.

There was nothing special about this fossil, unless the fact of being imbedded in a geological layer dating back to 30,000 and 50,000 years ago. Alexander Tsybankov kept the piece in his pocket and continued digging. Nothing found later, however, would be as revealing as the bone, so small, could, in the eyes of a layman look of these boulders entering the shoe. In fact, it was the paleontological record of a species hitherto unknown. That girl was not a Homo sapiens, either a copy of the Neanderthals become extinct. But it was undoubtedly human.

Two years of study in Novosibirsk, Russia; Leipzig, Germany, and California in the United States until the researchers have the evidence they needed to announce the scientific community what they had at hand. In 2010, an article published in Nature describing the discovery of the man Denisova, a human species that cohabited the planet with Neanderthals and modern humans for thousands of years. Genetic studies show that the three not only come up against - in fact, crossed by printing his legacy in the DNA of many people.

At the beginning of the research, scientists knew that there was a great possibility that the finger splinter found by Tosybankov belonging to a Homo sapiens who also lived in the cave - a refuge for the nomadic when the Siberian winds made the existence in almost impossible site. How Neanderthal bones had also been detected in Denisova Cave, scientists have DNA tests. They wanted to know if the finger fragment was a sapiens neanderthalensis or.

The result was surprising: neither. The genetic material simply did not fit. Russian researchers decided to seek help from American and German colleagues. It was in the laboratory of Svante Paabo of Evolutionary Anthropology Max Planck Institute in Leipzig, the identity of the denisovana girl began to unfold. Paabo is a regular visitor of the science pages of major newspapers and magazines in the world. With his microscope, the geneticist is rewriting the history of mankind - it was, for example, that by sequencing the complete genome of a Neanderthal, proved that there was sexual intercourse between that extinct species and modern man.
few data

Six years after the discovery of the finger fragment, still very little is known about this human mystery, which split from the common ancestor of Homo sapiens 600,000 years, running its own evolutionary path to be extinct around 50,000 years ago (which makes the little girl from the cave one of the last of its kind). "We do not know, for example, how they looked. They have genes in modern humans, suggest skin, eyes and dark hair. But we can not say for sure, that was how it looked, "says David Reich, a geneticist at Harvard University who was part of the team of scientists responsible for the genetic sequencing of denisovano man.

The clues they are very rare. Until last year, the only remnants were the girl's phalanx and a tooth of another individual, also found in Russian cave. In November, researchers at the Max Planck Institute announced the discovery of a molar. Three parts: that's all you have on the species. Unlike Neanderthals, no complete skeletons to determine the average height a facial or skull for reconstitution.

Susanna Sawyer, a researcher at the Max Planck signing the scientific article describing the third molar, points out that, in the absence of fossil, genetic analysis is that will unravel the history of the species. "The genes already show us some interesting things. For example, they are much closer to Neanderthals than modern man, "he says. The comparison of denisovano genome with current populations showed that the Melanesians of Papua New Guinea and the aborigines of Australia now share 5% of DNA with Denisovans. Philippine indigenous as manobos and mamanuas also has traits of the species in the genome.

Migration

The denisovana presence in Siberia, Southeast Asia and the Pacific islands suggests an extensive migratory pattern, says Joshua Akey, a researcher at the University of Washington, specializing in human evolution. He is the author of a study published two weeks ago in the journal Science, which describes the genetic heritage of Denisovans the peoples of Melanesia.

Scientists have sequenced the genome of 35 people from 11 localities in the Bismarck Archipelago, Papua New Guinea, and compared them to the DNA of extinct species. Matches found in important regions of the genome, such as associated with language and development of the brain. "The in-depth study of these regions can reveal us many things about the influence of Denisovans in modern human and help to understand a few more features that could be part of this people," he says.