Washington - Modern humans may have left Africa thousands of years earlier than previously thought, turning right and heading across the Red Sea into Arabia rather than following the Nile to a northern exit, an international team of researchers says.

Stone tools discovered in the United Arab Emirates indicate the presence of modern humans between 100,000 and 125,000 years ago, the researchers report in Friday’s edition of the journal Science.

While science has generally accepted an African origin for humans, anthropologists have long sought to understand the route taken as these populations spread into Asia, the Far East and Europe. Previously, most evidence has suggested humans spread along the Nile River valley and into the Middle East about 60,000 years ago.

“There are not many exits from Africa. You can either exit” through Sinai north of the Red Sea or across the straits at the south end of the Red Sea, explained Hans-Peter Uerpmann of the Center for Scientific Archaeology of Eberhard-Karls University in Tuebingen, Germany.

“Our findings open a second way which, in my opinion, is more plausible for a massive movement than the northern route,” he said in a telephone briefing.

Because of the different climate at the time, Arabia was moister and would have been a grassland with plenty of animals for prey, he added.

And the lower sea levels at that time meant that the narrow point at the southern end of the Red Sea would have separated Africa and Arabia by between one-half and 2 1/2 miles, said Adrian G. Parker of Oxford Brookes University in England.

That should not have been a difficult crossing for people used to dealing with east African lakes and rivers where they used rafts or boats, Uerpmann said.

The techniques used to make the hand axes, scrapers and other tools found at Jebel Faya in Sharjah Emirate suggest they were produced by people coming from somewhere else, said Anthony E. Marks of Southern Methodist University in Dallas, adding that there are similar tools made about that time in East Africa.

“If these tools were not made by modern man, who might have made them?,” Marks asked. “Could Neanderthals have made them?”

Neanderthals were mainly in Europe and migrated into Russia but “there is no evidence for any Neanderthals south of that” zone at that time, he said. “To suggest one group of Neanderthals took a turn south and went several thousand kilometers … seems to me a very difficult explanation and one that doesn’t follow any reasonable logic.”

The tools were dated using optically stimulated luminescence, which is able to date the sand grains on top of the tools and determine when they were last exposed to light, explained Simon J. Armitage of the University of London.

The discovery “points convincingly to an early dispersal of (anatomically modern humans) along a southern route, from eastern Africa into South Arabia,” said G. Philip Rightmire of Harvard University, who was not part of the research team.

Rightmire said “it is reasonable to hypothesize that Arabia represents a separate center for population expansion, in addition to the northern Levantine corridor. This hypothesis remains to be tested, as new evidence is compiled.”

The research was supported by the government of Sharjah, Heidelberg Academy of Sciences, Humboldt Foundation, Oxford Brookes University and the German Science Foundation.

AP

WASHINGTON — Prehistoric people in southern Africa developed a highly skilled way of shaping stones into sharp-edged tools long before Europeans did, suggested a study released Thursday.

A technique known as pressure-flaking, which scientists previously thought was invented in Europe some 20,000 years ago, involves using an animal bone or some other object to exert pressure near the edge of a stone piece and precisely carve out a small flake.

Researchers from the University of Colorado at Boulder examined stone tools dating from the Middle Stone Age, some 75,000 years ago, from Blombos Cave in what is now South Africa.

The team found that the tools had been made by pressure flaking, whereby a toolmaker would typically first strike a stone with hammer-like tools to give the piece its initial shape, and then refine the blade’s edges and shape its tip.

The technique provides a better means of controlling the sharpness, thickness and overall shape of two-sided tools like spearheads and stone knives, said Paola Villa, a curator at the University of Colorado Museum of Natural History and a co-author of the study published in the journal Science.

“Using the pressure flaking technique required strong hands and allowed toolmakers to exert a high degree of control on the final shape and thinness that cannot be achieved by percussion,” Villa said.

“This control helped to produce narrower and sharper tool tips.”

To arrive at their conclusion that prehistoric Africans could have been the first to use pressure flaking to make tools, the researchers compared stone points, believed to be spearheads, made of silcrete — quartz grains cemented by silica — from Blombos Cave, and compared them to points that they made themselves by heating and pressure-flaking silcrete collected at the same site.

The similarities between the ancient points and modern replicas led the scientists to conclude that many of the artifacts from Blombos Cave were made by pressure flaking, which scientists previously thought dated from the Upper Paleolithic Solutrean culture in France and Spain, roughly 20,000 years ago.

“This finding is important because it shows that modern humans in South Africa had a sophisticated repertoire of toolmaking techniques at a very early time,” said Villa.

The authors speculated that pressure flaking may have been invented in Africa and only later adopted in Europe, Australia and North America.

- AFP

Scientist published the results of a 10 years study about the diversity of Genes on the African continent. The research covered 121 African populations, four African American populations and 60 non-African. According to the Scientists there is more genetic diversity in Africa then anywhere else in the world. The study correlated cultural as well as linguistic characteristics with genetic pattern of different populations. The analysis revealed that the exodus of the first humans out of Africa must have taken place through a gateway near the middle of the Read Sea in today’s Eritrea, Sudan or Egypt. Read More Science Centric.