Study of Teeth Indicates Europeans More Asian

WASHINGTON -- Early human-like residents of Europe may have arrived out of Asia, rather than just Africa.

An international team of researchers reports in Monday's online edition of Proceedings of the National Academy of Sciences that Asians appear to have played a larger part in the settlement of Europe than did Africans.

The team led by Maria Martinon-Torres of the National Center for the Investigation of Human Evolution, in Burgos, Spain, reached that conclusion after analyzing more than 5,000 fossil teeth from early hominins, an early form of human predecessors.

After studying ancient teeth from Africa, Asia and Europe, the researchers report that early European populations had more Asian features than African ones.

That conclusion also supports the theory that the development of the genus Homo -- modern humans are Homo sapiens -- occurred both in Africa and Asia.

The teeth studied were from the genera Homo and the earlier Australopithecus.

"The history of human populations in Eurasia may not have been the result of a few high-impact replacement waves of dispersals from Africa, but a much more complex puzzle of dispersals," Martinon-Torres' team wrote.

The differences in tooth formation, dimensions and shapes in Europe and Asia and that of Africa suggest separate evolutionary courses for a long period, they said.

That doesn't mean there was no genetic flow between Africa and Eurasia, but rather that the Eurasians were probably descendants of an ancient out-of-Africa exodus, they said.

Milford Wolpoff, an anthropologist at the University of Michigan, noted that dental evidence is always difficult to work with and said this research team did "a very good job."

The idea that human evolution involved small and relatively isolated populations for much of its history, with a migration out of Africa and other migrations between continents, "is in concordance with the interpretations of paleoanthropologists," he said.

"It may be in different languages, but we are singing the same song," said Wolpoff, who was not part of the research team.

The research was supported by the Spanish Ministry of Science and Education, Fundacion Caja Madrid, Fundacion Atapuerca, Fundacion Duques de Soria and the Georgian National Museum.

On the Net:

Proceedings of the National Academy of Sciences: http://www.pnas.org

New tests ordered

When the first Neanderthal studies were published in 1997, Thorne had retired but at the request of the Aboriginal council, he still safeguarded the Mungo fossils. Because three more sophisticated dating technologies were now available, he ordered new tests on 13 of the individuals in his care, and the results gave him a shock.

Mungo Man was 60,000 years old

The ages came back first. Using the new technologies, his team found that the small-boned Mungo Lady and Mungo Man were actually 60,000 years old twice as old as anyone had guessed. Thorne saw these dates as a crushing blow to the Out-of-Africa theorists. No matter what his opponents said, there wasn't enough time on their 120,000 year clock for Homo sapiens to leave Africa, dash up to China, evolve from rugged Africans into small-framed Asians, invent boats, sail to Australia, march to the interior, get sick, and die. How much simpler everyone's life would be, he thought, if anthropologists could agree that some of the players in this drama had reached China 1.5 million years ago and continued to evolve there

mtDNA of same 13 individuals

After the dating, Gregory Adcock, a doctoral student in genetics at Australian National University, decided to check all 13 fossils for mtDNA. But first he set up stringent procedures to avoid contaminating the specimens and he alone handled the specimens. Once he'd perfected handling techniques, he drilled into each fossil and took a sample from the bone's interior, where no one could ever have touched it. Of more than 60 samples he analysed he reported ten of the 13 had yielded DNA.

His mtDNA signature was unique

The results were nothing less than remarkable: Among the 10 successful extractions was the world's oldest known human DNA plucked from none other than Mungo Man. (No DNA was recovered from Mungo Lady, perhaps because she had been cremated.) Mungo Man also appeared to mock the findings of previous scientists: His mtDNA signature did not match anyone's, living or fossil, on Earth. There was no evidence that he was genetically related to ancient Africans.