FYI: Australian evidence for Out of Africa theory . . .

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http://www.nhm.ac.uk/about-us/news/2007/may/news_11665.html

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  Australian evidence for Out of Africa theory


    09 May 2007

A replica of a gracile Australian Homo sapiens skull about 40,000 years
old.

A replica of a gracile Australian /Homo sapiens/ skull about 40,000
years old.

*Scientists have produced DNA evidence confirming that Australia and New
Guinea's earliest settlers came from one small group of people, the same
group all modern humans came from.*

Genetic data suggest that this group of modern humans, or / *Homo
sapiens* /, evolved in Africa and migrated out about 50-70,000 years
ago. As well as remaining in Africa, they spread throughout the world to
become the human race we know today. This is known as the *Out of Africa
theory* , a theory that was originally developed from fossil evidence,
but is now supported by both genetic and archaeological data.

Some scientists disagree with this theory and have suggested that modern
humans descended from, or interbred with, more ancient human relatives
outside of Africa such as / *Homo erectus* / (in Asia) and the
*Neanderthals* (in Europe).


          Comparing genetic information

Claimed inconsistencies in the fossil and archaeological record of early
modern humans in Australia and New Guinea led some people to question
the Out of Africa theory.

However, an international team of scientists has compared genetic
information from native populations in Australia and New Guinea with
those from other modern people. They found no evidence of a genetic
inheritance from non-African ancestors, indicating that they share the
same African origins as the rest of us.

'For the first time,' says Dr Peter Forster, one of the leaders of the
research, 'this evidence gives us a genetic link showing that the
Australian Aboriginal and New Guinean populations are descended directly
from the same specific group of people who emerged from the African
migration.'


          Support for Out of Africa

Chris Stringer, human origins expert at the Natural History Museum says,
'This new study clearly supports a strong Out of Africa model i.e. one
without archaic hybridisation.'

'It provides the first large and detailed comparison of Australian
female-inherited (mitochondrial) and male-inherited (Y chromosome) DNA,
and indicates there was apparently one colonisation of Australia and New
Guinea about 50,000 years ago by modern humans who had recently
dispersed from Africa.'

'The important native population of Tasmania was not included in this
work, but it provides an excellent comparative base for such studies in
the future.'


          Australian inconsistencies

Scientists have debated the origins of native Australians and New
Guineans because some believe that there are inconsistencies in the
fossil and archaeological records.

Early modern human skeletons dating from about 40,000 years ago have
been uncovered showing a *slender or gracile form*, while some later
material shows a much more *robust form* .

Some scientists suggested that this robusticity could indicate
interbreeding with, or descent from, more ancient human relatives like
/H. erectus/ .


          Tools and dingos

An increase in the abundance and complexity of Australian tools after
10,000 years ago, and the arrival of the first domesticated dogs
(dingos), also suggested extensive migrations into the continent at that
time.

However, this new research helps to clarify the situation. The
populations of Australia and New Guinea diverged quite early, and
*evolved in relative isolation* , and there is scant evidence of gene
flow into Australia after the original migration.

Chris adds, 'The results certainly fit with my view of human evolution
in Australia. There is considerable variation in size and robusticity in
ancient Australian populations, but it looks like this variation
developed within the continent between 50,000 and 10,000 years ago,
without the influence of interbreeding or descent from archaic populations.'

The study was carried out by an international team of scientists,
including the  *Cambridge and Anglia Ruskin Universities.* The work is
reported in the new issue of *Proceedings of the National Academy of
Sciences* .
"

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