This blast of evidence
conforms totally to the Atlantean global distribution which surely operated
gold mining throughout this region circa 3000 BC through 1159 BC.
The genetic signature
described here conforms precisely to the Atlantean signature we have identified
earlier. Thus it is pretty obvious that
this DNA injection came by sea and likely had nothing to do with internal
migrations. Thus the maps are at best
misleading.
This is good news for
the Atlantean conjecture. The DNA needed
to be there but could easily have been locally isolated at the time. I have the same problem with China in
particular and the Olmec. The core
population carrying the DNA could have even moved on in the face of local
pressure.
It also demonstrates
how thoroughly a majority population can subsume a minority population of
seamen who have no plans to colonize.
That is why much of the Atlantean DNA diaspora became invisible.
Humanity's forgotten
return to Africa revealed in DNA
Call
it humanity's unexpected U-turn. One of the biggest events in the history of our species
is the exodus out of Africa some 65,000
years ago,
the start ofHomo sapiens' long march
across the world. Now a study of southern African genes shows that,
unexpectedly, another migration took western Eurasian DNA back to the very
southern tip of the continent 3000 years ago.
According
to conventional thinking, the Khoisan
tribes of southern Africa, have lived in near-isolation from the rest of
humanity for thousands of years. In fact, the study shows that some of their
DNA matches most closely people from modern-day southern Europe, including
Spain and Italy.
Because Eurasian people also carry traces
of Neanderthal DNA,
the finding also shows – for the first time – that genetic material from our
extinct cousin may be widespread in African populations.
The
Khoisan tribes of southern Africa are hunter-gatherers and pastoralists who
speak unique click languages. Their extraordinarily diverse gene pool split
from everyone else's before the African exodus.
Ancient
lineages
"These
are very special, isolated populations, carrying what are probably the most
ancient lineages in human populations today," says David
Reich of
Harvard University. "For a lot of our genetic studies we had treated them
as groups that had split from all other present-day humans before they had
split from each other."
So
he and his colleagues were not expecting to find signs of western Eurasian
genes in 32 individuals belonging to a variety of Khoisan tribes. "I think
we were shocked," says Reich.
The
unexpected snippets of DNA most resembled sequences from southern Europeans,
including Sardinians, Italians and
people from the Basque region (see "Back to Africa – but from where?"). Dating methods suggested
they made their way into the Khoisan DNA sometime between 900 and 1800 years
ago – well before known European contact with southern Africa (see map).
Archaeological
and linguistic studies of the region can make sense of the discovery. They
suggest that a subset of the Khoisan, known as the Khoe-Kwadi speakers, arrived
in southern Africa from east Africa around 2200 years ago. Khoe-Kwadi speakers
were – and remain – pastoralists who make their living from herding cows and
sheep. The suggestion is that they introduced herding to a region that was
otherwise dominated by hunter-gatherers.
Khoe-Kwadi
tribes
Reich
and his team found that the proportion of Eurasian DNA was highest in
Khoe-Kwadi tribes, who have up to 14 per cent of western Eurasian ancestry.
What is more, when they looked at the east African tribes from which the
Khoe-Kwadi descended, they found a much stronger proportion of Eurasian DNA –
up to 50 per cent.
That
result confirms a 2012 study by Luca Pagani of the Wellcome Trust Sanger
Institute in Hinxton, UK, which found non-African genes in people living
in Ethiopia.
Both the 2012 study and this week's new results show that the Eurasian genes
made their way into east African genomes around 3000 years ago. About a
millennium later, the ancestors of the Khoe-Kwadi headed south, carrying a
weaker signal of the Eurasian DNA into southern Africa.
The
cultural implications are complex and potentially uncomfortably close to
European colonial themes. "I actually am not sure there's any population
that doesn't have west Eurasian [DNA]," says Reich.
"These
populations were always thought to be pristine hunter-gatherers who had not
interacted with anyone for millennia," says Reich's collaborator,
linguist Brigitte Pakendorf of the University of Lyon in
France. "Well, no. Just like the rest of the world, Africa had population
movements too. There was simply no writing, no Romans or Greeks to document
it."
Twist
in tale
There's
one more twist to the tale. In 2010 a research team – including Reich –
published the first draft genome of a
Neanderthal.
Comparisons with living humans revealed traces of Neanderthal DNA in all humans
with one notable exception: sub-Saharan peoples like the Yoruba and Khoisan.
That
made sense. After early humans migrated out of Africa around 60,000 years ago,
they bumped into Neanderthals somewhere in what is now the Middle East. Some
got rather cosy with each other. As their descendants spread across the world to Europe, Asia and
eventually the Americas, they spread bits of Neanderthal DNA along with their own
genes. But because those descendants did not move back into Africa until
historical times, most of this continent remained a Neanderthal DNA-free zone.
Or
so it seemed at the time. Now it appears that the Back to Africa migration 3000
years ago carried a weak Neanderthal genetic signal deep into the homeland.
Indeed one of Reich's analyses, published last month, found Neanderthal traces
in Yoruba DNA (Nature, DOI: 10.1038/nature12886).
In
other words, not only is western Eurasian DNA ancestry a global phenomenon, so
is having a bit of Neanderthal living on inside you.
Back
to Africa – but from where?
Reich
and his colleagues found that DNA sequences in the Khoisan people most closely
resemble some found in people who today live in southern Europe. That, however,
does not mean the migration back to Africa started in Italy or Spain. More
likely, the migration began in what is now the Middle East.
We
know that southern Europeans can trace their ancestry to the Middle East.
However, in the thousands of years since they – and the ancestors of the
Khoisan – left the region, it has experienced several waves of immigration.
These waves have had a significant effect on the genes of people living in the
Middle East today, and and means southern Europeans are much closer to the
original inhabitants of the Levant than modern-day Middle Easterners.
No comments:
Post a Comment