Genetics: "World Populated By Single African Tribe"

It
is thought that changes in the climate between 90,000 and 70,000 years
ago caused sea levels to drop dramatically and allowed the crossing of
the Red Sea to take place. The findings are to be revealed in a new BBC
Two documentary series, “The Incredible Human Journey,” that traces the
prehistoric origins of the human species. Dr Peter Forster, a senior
lecturer in archaeogenetics at Anglia Ruskin University in Cambridge who
carried out some of the genetic work, said: “The founder populations
cannot have been very big. We are talking about just a few hundred
individuals.”

Homo
sapiens, known casually as “modern humans”, are thought to have first
evolved around 195,000 years ago in east Africa – the earliest remains
from that time were uncovered near the Omo River in Ethiopia. It is
thought that by 150,000 years ago these early modern humans had managed
to spread to other parts of Africa and fossilised remains have been
found on the Cape of Good Hope in South Africa. The earliest homo sapien
remains found outside of Africa were discovered in Israel and are
thought to be around 100,000 years old. They are remains of a group that
left Africa through what is now the Sahara desert during a brief period
when the climate grew wetter, turning the desert green with vegetation.
This excursion, however, failed and the population died out when the
climate started to dry out again.

While
there are 14 ancestral populations in Africa itself, just one seems to
have survived outside of the continent. The latest genetic research has
shown that it was not until around 70,000 years ago that humans were
able to take advantage of falling sea levels to cross into Arabia at the
mouth of the Red Sea, which is now known as the Gate of Grief. At the
time the 18 mile gap between the continents would have dropped to just 8
miles. It is not clear how they might have made such a journey but once
a cross, the humans were able to spread along the Arabian coast where
fresh water springs helped support them.

It
has long been assumed that humans success in spreading around the world
was due to their adaptability and hunting skills. The latest research,
however, suggests that the very early human pioneers who ventured out of
Africa owe far more of their success to luck and favourable changes in
climate change than had previously been realised. Dr Stephen
Oppenheimer, a geneticist at the school of anthropology at Oxford
University who has also led research on the genetic origins of humans
outside Africa, said: “What you can see from the DNA of all non Africans
is that they all belong to one tiny African branch that came across the
Red Sea.

“If it was easy
to get out of Africa we would have seen multiple African lineages in
the DNA of non-Africans but that there was only one successful exit
suggests it must have been very tough to get out. It was much drier and
colder then.” Within around 5,000 years some of these early human
pioneers had managed to spread along the edge of the Indian Ocean and
down through south east Asia and arriving in Australia around 65,000
years ago. Others made their way north through the Middle East and
Pakistan to reach central Asia.

Around
50,000 years ago they also began spreading into Europe via the Bosporus
at the Istanbul Strait. Again low sea levels allowed them to almost
walk into Europe. Once there they will have encountered Neanderthals,
who, with bigger bodies were more adapted to the cold weather at the
time, had been living in Europe for nearly a quarter of a million years
but are thought to have died out due to changes in the climate.

By
25,000 years ago humans had spread into northern Europe and Siberia and
then walked across the Bering land bridge into Alaska around 20,000
years ago. The peak of the last ice age, which was reached around 19,000
years ago, saw human populations pushed south by the extreme cold and
it was about 15,000 years ago that South America became the last
continent on the planet to be colonised. Britain and northern
Scandinavia is thought to have been recolonised by modern humans after
the last ice age between 10,000 and 8,000 years ago.

Dr
Alice Roberts, an anatomist at Bristol University who presents The
Incredible Human Journey, said: “There seems to have been a huge amount
of luck involved as they were totally at the whim of the climate. The
climate changed at just the right time to allow them to expand out of
Africa and they were allowed to expand geographically as a result, but
when the climate changed they shrank back again.”

The
idea that all non-African humans are descended from a single group of
individuals contradicts previous theories that the different modern
races evolved seperately from an earlier human ancestor known as Homo
erectus in different parts of the world. Archaeologists in China, for
example, believe they have strong evidence that the Chinese evolved
directly from a lineage of Homo erectus that arrived in China 2 million
years ago and not from African Homo sapiens. But recent genetic work at
Fudan University in Shanghai tested the Y chromosomes of more than
12,000 men currently living in different parts of China and found that
they all descended from the original African humans. Professor Li Jin, a
geneticist at Fudan University in Shanghai whose laboratory carried out
the research, said: “We did not find a single individual that could be
considered the decendants of homo erectus in China. “I think we should
all be happy with that, as after all, it means that people from all over
the world are not all that different from each other.”

- http://www.telegraph.co.uk/science/science-news/5299351/African-tribe-populated-rest-of-the-world.html

How about that, we’re all brothers and sisters after all. 

So just how astonishingly stupid is racism? Think about it…

- CP