Modern humans not uniquely evolved species

September 6th, 2011 - 4:49 pm ICT by IANS  

Washington, Sep 6 (IANS) Homo sapiens, the species that all human beings are believed to belong to, might have crossbred with others, says a study.

Homo sapiens, believed to have originated in Africa, possibly interbred with ancient forms of the genus Homo, that includes the present day and other closely related species of humans.

Homo comprises Homo erectus, the “upright walking man”, Homo habilis, the “tool-using man” and Homo neanderthalensis, the first artists of cave-painting fame.

Analysis of the ancient DNA from Neanderthal bones suggest interbreeding did occur after modern humans quit their evolutionary cradle in Africa for cooler Eurasian climes. But what had happened in Africa remained a mystery - until now.

A team led by Michael Hammer, research scientist with the University of Arizona’s Arizona Research Labs, suggests that anatomically modern humans were not so unique that they remained separate.

“We found evidence for hybridization between modern humans and archaic forms in Africa,” said Hammer, the journal Proceedings of the National Academy of Sciences reports.

Recent advances in molecular biology have made it possible to extract DNA from fossils tens of thousands of years old and compare it to that of modern counterparts, according to an Arizona statement.

However, Hammer said: “We don’t have fossil DNA from Africa to compare with ours.”

“We couldn’t look directly for ancient DNA that is 40,000 years old and make a direct comparison,” said Hammer.

“Instead, we looked at DNA from modern humans belonging to African populations and searched for unusual regions in the genome,” he said.

The researchers used simulations to predict what ancient DNA sequences would look like, had they survived within the DNA of our own cells.

According to Hammer, the first signs of anatomically modern features appeared about 200,000 years ago.

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