Wednesday, November 2, 2011

Siberians share DNA with extinct human species


Siberians share DNA with extinct human species, Researchers have found that people in East Asia share genetic material with Denisovans, who got the name from the cave in Siberia where they were first found.

The new study covers a larger part of the world than earlier research, and it is clear that it is not as simple as previously thought. siberians DNA extinct humans Professor Mattias Jakobsson, of Uppsala University in Sweden who conducted the study together with graduate student Pontus Skoglund, said hybridisation took place at several points in evolution and the genetic traces of this can be found in several places in the world.

He said: "We'll probably be uncovering more events like these.

"Previous studies have found two separate hybridisation events between so-called archaic humans - different from modern humans in both genetics and morphology - and the ancestors of modern humans after their emergence from Africa.

"There was hybridisation between Neanderthals and the ancestors of modern humans outside of Africa and hybridisation between Denisovans and the ancestors of indigenous Oceanians.

"The genetic difference between Neanderthals and Denisovans is roughly as great as the maximal level of variation among us modern humans."

The Uppsala scientists' study demonstrates that hybridisation also occurred on the East Asian mainland.

The connection was discovered by using genotype data in order to obtain a larger data set.

Complete genomes of modern humans are only available from some dozen individuals today, whereas genotype data is available from thousands of individuals.

These genetic data can be compared with genome sequences from Neanderthals and a Denisovan which have been determined from archeological material.

Only a pinky finger and a tooth have been described from the latter.

Genotype data stems from genetic research where hundreds of thousands of genetic variants from test panels are gathered on a chip.

However, this process leads to unusual variants not being included, which can lead to biases if the material is treated as if it consisted of complete genomes.