9525Meet the ancestors: DNA study pinpoints Namibia as home to the world's most ancient race
- Jan 11, 2011Meet the ancestors: DNA study pinpoints Namibia as home to the world's
most ancient race
Last updated at 4:38 PM on 1st May 2009
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Scientists have long known that humans originated in Africa, but now a
groundbreaking DNA study has revealed our 'Garden of Eden' is likely
to be on the South African-Namibian border.
For it is the San people, hunter-gatherers in this area for thousands
of years, who researchers now believe are the oldest human population
They are descended from the earliest human ancestors from which all
other groups of Africans stem and, in turn, to the people who left the
continent to populate other corners of the planet.
The San people seen here tracking wildebeest in Namibia, have the
greatest genetic diversity in Africa
Researchers conducting the largest study of African genetic diversity
came to this conclusion as the San were shown to be the most diverse.
The origin of a species is taken to be the place where people show the
most genetic diversity because of the time it takes for genes to
evolve. The DNA tests therefore suggest the San are the oldest
continuous population of humans on the Earth.
The research published today in the online journal Science also showed
that nearly three-quarters of African-Americans can trace their
ancestry to West Africa.
The 10-year-study was led by Professor Sarah Tishkoff, a geneticist at
the University of Pennsylvania.
The San people live on the Namibia-Angola border
She trekked across remote and dangerous areas of the continent with an
international team collecting DNA samples from more than 3,000 modern
Africans from 121 distinct populations.
Often working in primitive conditions, the researchers sometimes had
to resort to using a car battery to power their equipment.
The tests revealed they had all descended from just 14 ancestral
populations, and the languages they spokes were closely correlated
with the variation of their genes.
The study also suggests that a small group of 150 Africans, who went
on to populate the rest of the world, first left their continent from
the Red Sea.
The researchers found people who lived in Sudan had genetic markers
which suggested they were related to the group who moved abroad 50,000
'The human genome describes the complexity of our species,' added
Muntaser Ibrahim of the department of molecular biology at the
University of Khartoum, Sudan.
'Now we have spectacular insight into the history of the African
population ... the oldest history of mankind.
'Everybody's history is part of African history because everybody came
out of Africa.'
Before this study very little was known about the genetic variation in
Africans, knowledge that is vital to understanding why diseases have a
greater impact in some groups than others and in designing ways to
counter those illnesses.
Scott M. Williams of Vanderbilt University noted that constructing
patterns of disease variations can help determine which genes
predispose a group to a particular illness.
This study 'provides a critical piece in the puzzle', he said. For
example, there are clear differences in prevalence of diseases such as
hypertension and prostate cancer across populations, Mr Williams said.
The San people, hunter-gatherers in south-west Africa for thousands of
years, are believed to be the oldest population of humans on Earth
Christopher Ehret from the University of California, Los Angeles,
compared genetic variation among people to variations in language.
There are an estimated 2,000 distinct language groups in Africa broken
into a few broad categories, often but not always following gene flow.
Movement of a language usually involves arrival of new people, Mr
Ehret noted, bringing along their genes.
But sometimes language is brought by a small 'but advantaged' group
which can impose their language without significant gene flow.
The study also found that about 71 per cent of African-Americans can
trace their ancestry to western African origins.
They also have between 13 per cent and 15 per cent European ancestry
and a smaller amount of other African origins.
There was 'very little' evidence for American Indian genes among
African-Americans, Tishkoff said.
Ehret added that only about 20 per cent of the Africans brought to
North America made the trip directly, while most of the rest went
first to the West Indies.
And, he added, some local African-American populations, such as the
residents of the sea islands off Georgia and South Carolina, can trace
their origins to specific regions such as Sierra Leone and Guinea.
The study was funded by the National Cancer Institute, the National
Institutes of Health, the Advanced Computing Center for Research and
Education at Vanderbilt University, the L.S.B. Leakey and Wenner Gren
Foundation, the National Science Foundation, the David and Lucile
Packard and Burroughs Wellcome foundations.
Read more: http://www.dailymail.co.uk/sciencetech/article-1176140/Meet-ancestors-DNA-study-pinpoints-Namibia-home-worlds-ancient-race.html#ixzz1AmE8wTYS
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