DNA Study: European Genes went from India

May 19th

thanks to reader siva.

 

more nails in the coffin of the aryan invasion fairy-tale. i posted a similar article a while ago on this blog.

 

but i do love the name of the fellow quoted below: how ironically appropriate that it should be a macaulay! this is one of god's little mischiefs.

 

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http://www.nytimes.com/2005/05/13/science/13migrate.html?adxnnl=1&adxnnlx=1116180255-HCwNSux1xetEdoSaH/eLpA&pagewanted=print

Actual article:

DNA Study Yields Clues on First Migration of Early Humans
By NICHOLAS WADE
By studying the DNA of an ancient people in Malaysia, a team of
geneticists  says it has illuminated many aspects of how modern humans
migrated from  Africa.

The geneticists say there was only one migration of modern humans out of
Africa; that it took a southern route to India, Southeast Asia and
Australia; and that it consisted of a single band of hunter-gatherers,
probably just a few hundred people strong.

Because these events occurred in the last Ice Age, when Europe was at
first  too cold for human habitation, the researchers say, it was
populated only  later, not directly from Africa but as an offshoot of the
southern  migration. The people of this offshoot would presumably have
trekked back  through the lands that are now India and Iran to reach the
Near East and  Europe.

The findings depend on analysis of mitochondrial DNA, a type of genetic
material inherited solely through the female line. They are reported today
in Science by a team of geneticists led by Dr. Vincent Macaulay of the
University of Glasgow.

Everyone in the world can be placed on a single family tree, in terms of
their mitochondrial DNA, because everyone has inherited that piece of DNA
from a single woman, the mitochondrial Eve, who lived some 200,000 years
ago.

There were, of course, many other women in that ancient population. But
over  the generations, one mitochondrial DNA replaced all the others
through the  process known as genetic drift.

With the help of mutations that have built up on the one surviving copy,
geneticists can arrange people in lineages and estimate the time of origin
of each lineage.

With this approach, Dr. Macaulay's team calculates that the emigration
from  Africa occurred 65,000 years ago, pushed along the coasts of India
and  Southeast Asia and reached Australia by 50,000 years ago, the date of
the  earliest known archaeological site there.

The Malaysian people whom the geneticists studied are the Orang Asli. The
term means "original men" in Malay.

They are probably descended from this first migration, because they have
several ancient mitochondrial DNA lineages that are found nowhere else.

These lineages are 42,000 to 63,000 years old, the geneticists say.
Subgroups of the Orang Asli, like the Semang, have probably been able to
remain intact because they adapted to the harsh existence of living in
forests, said Dr. Stephen Oppenheimer, the member of the geneticists' team
who collected blood samples in Malaysia.

Some archaeologists theorize that Europe was colonized by a second
migration  that traveled north out of Africa. This fits with the earliest
known modern  human sites, dating from 45,000 years ago in the Levant and
40,000 years ago  in Europe.

Dr. Macaulay's team says there could have been just one migration, not
two,  because the mitochondrial lineages of everyone outside Africa
converge at  the same time to the same common ancestors. Therefore, people
from the  southern migration, probably in India, must have struck inland
to reach the  Levant and, later, Europe, the geneticists say.

Dr. Macaulay said it was not clear why just one group succeeded in leaving
Africa. One possibility is that because the migration occurred by
continuous  population expansion, leaving people in place at each site,
the first  emigrants may have blocked others from leaving. Another is that
the terrain  was so difficult for hunter-gatherers, who carry all their
belongings with  them, that only one group succeeded in the exodus.

Although there is general but not complete agreement that modern humans
emigrated from Africa in recent times, there is still a difference between
geneticists and archaeologists about its a timing. Archaeologists tend to
view the genetic data as providing invaluable information about the
interrelationship between groups, but they place less confidence in the
dates derived from genetic family trees.

There is no evidence of modern humans outside Africa earlier than 50,000
years ago, said Dr. Richard Klein, an archaeologist at Stanford. Also, if
something happened 65,000 years ago to allow people to leave Africa, as
Dr.  Macaulay's team suggests, there should surely be some record of that
in the  archaeological record in Africa, Dr. Klein said. Yet signs of
modern human  behavior do not appear in Africa until 50,000 years ago, the
transition  between the Middle and Later Stone Ages, he said.

"If they want to push such an idea, find me a 65,000-year-old site with
evidence of human occupation outside of Africa," Dr. Klein said.

Geneticists counter that many of the coastline sites occupied by the first
emigrants would now lie under water, because the sea level has risen more
than 200 feet since the last Ice Age. Dr. Klein expressed reservations
about  that argument, noting that people would not wait for the slowly
rising sea  levels to overwhelm them but would build new sites farther
inland.

Dr. Macaulay said genetic dates had improved in recent years, now that it
is  affordable to decode the whole ring of mitochondrial DNA, and not just
a  small segment.

But he said he agreed "that archaeological dates are much firmer than the
genetic ones" and that it was possible his 65,000-year date for the
African  exodus was too old.

Dr. Macaulay's team has been able to estimate the size of the population
in  Africa from which the founders descended. The calculation indicates a
maximum of 550 women. The true size may have been considerably less. This
points to a single group of hunter-gatherers, perhaps a couple of hundred
strong, as the ancestors of all humans outside of Africa, Dr. Macaulay
said.