Australia Challenges Out-of-Africa Theory

ByABC News

S Y D N EY, Jan. 9, 2001 -- Australian scientists saidtoday they had analyzed the oldest DNA ever taken from humanremains, and that the results challenge the theory that modernhumans evolved from African ancestors alone.

Researchers at Australian National University said they hadanalyzed DNA taken from remains unearthed in 1974 at Lake Mungoin the state of New South Wales. Dating in May 1999 put the ageof the skeletal remains at between 56,000 and 68,000 years old.

ANU anthropologist Alan Thorne said that neither “MungoMan’s” completely modern skeleton nor its DNA had any linkswith human ancestors from Africa found in other parts of theworld.

“Neither of them [the skeleton or DNA] show any evidencethat they ever were in Africa,” Thorne told Reuters. “There’smodern humans in Australia that have nothing to do with Africaat all.”

The findings, revealed in The Australian newspaper today, challenge the prevailing “out of Africa” theory ofevolution because “Mungo Man” has a genetic line which hasvanished yet his skeleton is completely modern.

The “out of Africa” theory holds that modern humans evolvedfrom a common homo erectus ancestor in Africa.

Homo sapiens then left Africa and spread across the worldbetween 150,000 and 100,000 years ago.

The ANU researchers say that because Mungo Man is modernanatomically, yet has a vanished DNA line, it means at leastone group of homo erectus’ descendants evolved outside ofAfrica.

Under the counter “regional continuity” theory which Thornesupports, modern man evolved from homo erectus in severaldifferent places — what is now Africa, Europe, east Asia andwest Asia — followed by interbreeding between the regions.

“Everywhere was becoming modern at roughly the same rate,”Thorne said. “As they are today, genes were flowing fromShanghai to Paris, from Singapore to Cape Town.”

Genetic Fingerprint

DNA is a kind of genetic fingerprint unique to everyindividual and which transmits hereditary characteristics.

The ANU research says that Mungo Man’s mitochondrial DNAcontained different sequences of the four chemicals which formDNA to that which has been found in other remains. Mitochondriaare the energy packs within cells.

The previously oldest human DNA tested came fromNeanderthal remains — a 45,000-year-old specimen in westernGermany and 28,000-year-old remains from Croatia.

While the genetic footprint was different, ANU evolutionarygenetecist Simon Easteal said Mungo Man would have looked verymuch like modern humans.

“This individual has facial features, has morphology thatis essentially modern, that wouldn’t stand out in a crowdtoday,” Easteal told Reuters.

“If he was part of a wave of modern people that had comeout of Africa and spread, eventually reaching Australia, thenhis mitochondrial DNA would reflect that,” he said.

Thorne said the dating of Mungo Man meant there was nodoubt that ancestors of Australia’s Aborigines came to thecontinent from Asia about 70,000 years ago — some 30,000 yearsearlier than was thought.

“There’s no question that somewhere in southeast Asia iswhere watercraft got invented,” Thorne said. “The first oceaniccrossings were to Australia.”