By Paul Tait

SYDNEY (Reuters) - Modern humankind's evolutionary plot thickened
Wednesday when the man who discovered an Australian fossil whose DNA
promises to rewrite human history said the skeleton was not as old as it
has been claimed.

But geologist Jim Bowler, who discovered the ``Mungo Man'' fossil in a dry
lake bed in New South Wales state in 1974, did not challenge the theory
that his fossil's DNA proved modern man did not evolve from African
ancestors alone.

Australian National University (ANU) scientists said on Tuesday that tests
on mitochondrial DNA taken from bone chips from Mungo Man suggested he was
around 62,000 years old and whose DNA is the oldest genetic material ever
tested.

Bowler said their estimate was out by about 20,000 years.

But he did not dispute the ANU team's claim that Mungo Man challenged the
prevailing ``out of Africa'' theory of evolution because its completely
modern skeleton and DNA had no links with human ancestors from Africa
found in other parts of the world.

``The genetics and the mitochondrial data stand alone,'' Bowler told
Reuters.

``It wouldn't matter if it was 20,000 or 60,000 years -- to be extracting
mitochondrial DNA from that bone is extraordinary and the implications
don't change,'' he said.

ANU anthropologist Alan Thorne said Mungo Man supported the counter
``regional continuity'' theory of evolution because its DNA has a genetic
line which has vanished yet its skeleton is completely modern.

Vanished Line

The ``out of Africa'' theory holds that modern humans can be traced to
homo sapiens who evolved from homo erectus ancestors in Africa. Homo
sapiens then left Africa and moved around the world.

Thorne says that, because Mungo Man has a vanished DNA line, it means homo
erectus left Africa and then evolved into homo sapiens in other parts of
the world at the same time.

Bowler however disputes the ANU's claim that they have analyzed the oldest
DNA ever taken from human  remains. The ANU team says three different,
sophisticated types of testing in May 1999 fixed Mungo Man's age at
between 56,000 and 68,000 years.

Bowler said the ANU team missed important geological fieldwork providing
the skeleton's relationship with its surroundings and the layers above and
below the skeleton which fixed Mungo Man's age at between 40,000 and
45,000 years old. DNA has been tested from Neanderthal remains of about
the same age in western Germany.

``They failed to check the field relationships, which is a mortal sin for
earth scientists -- understandable for anthropologists but not for earth
scientists,'' Bowler said.

``On that basis their dates I believe are seriously in error.''

Thorne rejected Bowler's argument, saying the ANU tests were the most
sophisticated available.

``But it doesn't matter for this debate whether the genetic material is
40,000 or 60,000,'' Thorne told Reuters on Wednesday.

Bowler said he had fixed Mungo Man's age because geological tests had
identified when the lake began to dry out and because clay from the drying
lake floor had been found with the remains.

He unearthed Mungo Man after finding the tip of its cranium near the
surface of a sand dune in windswept Lake  Mungo, a dry creek bed about 500
miles west of Sydney.

It was found with its arms crossed over its pelvis and it was sprinkled
with a fine powder of red ochre, indicating it had been buried
ceremonially.

The skeleton is now kept under the ANU's protection in Canberra with the
permission of the area's Aboriginal elders.

The controversy over Mungo Man's age throws into dispute when the
ancestors of Aborigines first arrived in Australia from Asia, with
prevailing opinion at between 40,00 and 50,000 years ago.

POWRÓT