Neanderthal KhoiSan.
Andre Willers
25 Mar 2014
Synopsis :
Surprisingly , West Eurasian and Neanderthal genes have been
found in KhoiSan .
Discussion :
1.Genetic Study :
Ancient west Eurasian ancestry in
southern and eastern Africa
Significance
The hunter–gatherer
and pastoralist populations of southern Africa are among the culturally,
linguistically, and genetically most diverse human populations. However, little
is known about their history. We show that all of these populations have some
ancestry most closely related to Europeans and Middle Easterners and use this
to reconstruct the history of population movements between Eurasia, eastern
Africa, and southern Africa.
Abstract
The history of southern Africa
involved interactions between indigenous hunter–gatherers and a range of
populations that moved into the region. Here we use genome-wide genetic data to
show that there are at least two admixture events in the history of Khoisan
populations (southern African hunter–gatherers and pastoralists who speak
non-Bantu languages with click consonants). One involved populations related to
Niger–Congo-speaking African populations, and the other introduced ancestry
most closely related to west Eurasian (European or Middle Eastern) populations.
We date this latter admixture event to ∼900–1,800 y ago and show that it had the
largest demographic impact in Khoisan populations that speak Khoe–Kwadi
languages. A similar signal of west Eurasian ancestry is present throughout
eastern Africa. In particular, we also find evidence for two admixture events
in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of
which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the
allele frequencies of the putative west Eurasian population in eastern Africa
and show that this population is a good proxy for the west Eurasian ancestry in
southern Africa. The most parsimonious explanation for these findings is that
west Eurasian ancestry entered southern Africa indirectly through eastern
Africa.
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Neanderthal genes .
(Phys.org) —A team of researchers with
representatives from the U.S., Germany and France has found evidence of western
Eurasian genes in Khoisan tribes living in southern Africa. This suggests, the
researchers conclude in a paper they've had published in Proceedings of
the National Academy of Sciences, that a migration from the Middle East
back to Africa occurred approximately 3000 years ago.
Scientists believe humans evolved from ancestral
primates in Africa several hundred thousand years ago, but it wasn't until
approximately 65,000 years ago that they made their way out of Africa and into
the Middle East and eventually the rest of the world. Until recently, that
migration has been viewed by most scientists as a one-way trip. Gene studies
over the past several years has turned that thinking around, however, as its
been found that many people in several parts of Africa have European or Asian
gene segments in their DNA. In this latest study, the researchers have found
evidence of Eurasian genes in tribespeople who were thought to
have a purely African ancestry.
The Khoisan tribespeople of today still live much
as their ancestors did—they are hunter-gathers who are also pastoralists—they
are most familiar to westerners as the people who speak with distinctive
clicking noises. Until now, they were believed to have the purest African gene
pool due to their thousands of years of isolationist practices.
The team acquired DNA samples from 32 people
living in Khoisan tribes in southern Africa—an analysis revealed Eurasian gene
segments in all of them. But that wasn't the end of the story. To understand
how the gene fragments got into the Khoisan tribespeople, the researchers
turned to archeological and linguistic evidence to build a possible time-line
of events. In so doing, they've found what they believe to have been a
migration back into Africa by people of the Middle East (ancestors of the
people that migrated to Europe and Asia) approximately 3000 years ago. Those
people made their way to various parts of the continent, including a part of
eastern Africa from which the Khoisan tribespeople had migrated south approximately
900 and 1800 years ago.
The researchers found something else—the Khoisan
tribespeople also had snippets of Neanderthal DNA in their genes as
well—courtesy of their Eurasian heritage.
Explore further: Southern Europeans have North African genes
More information: Ancient west Eurasian ancestry in southern
and eastern Africa, Joseph K. Pickrell, PNAS, DOI: 10.1073/pnas.1313787111
Abstract
The history of southern Africa involved interactions between indigenous hunter–gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger–Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900–1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe–Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa.
The history of southern Africa involved interactions between indigenous hunter–gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger–Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900–1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe–Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa.
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2.Notice the correlations with the various collapses of the
Marib dam (Sha’aaba) in Yemen and eco-refugees to East Africa.
3This occurred when the Makgadigadi Sea was full and the
Mapungubwe ( http://en.wikipedia.org/wiki/Kingdom_of_Mapungubwe)
and Zimbabwe cultures (http://en.wikipedia.org/wiki/Zimbabwe
)
were active.
4. Earlier interactions took place .
5. Diseases :
Why were the KhoiSan a virgin population for many infectious
diseases (smallpox , flu , whooping cough , etc) did eventually did them in ?
A theory is that the drying-up of the Makgadigadi sea turned
the whole interior of Southern Africa into an impenetrable desert .
The KhoiSan flourished around the southern coasts , but were
isolated until Portuguese and Dutch deep-sea ships reached them .
Then they perished from plagues .
Because genes giving at least some protection against the
latest plagues never got to them at the tip of Southern Africa .
The only traders/travellers/slavers around that area at the
time were the Arabs in their dhows .
6.Why did the Arab trader dhows not go further south ?
The exact origins of the dhow are lost to
history. Most scholars believe that it originated in China between 600 B.C. to
600 A.D.
They got to present Maputo (26 degrees south) , but not
further south to Durban (30 degrees south)
Why ?
I can only think that the strong Southward Aghulhas current
and the weak and variable winds of the Horse Latitudes formed a very effective
barrier to a coast-hugger like a dhow ,
See http://geography.about.com/od/physicalgeography/a/tradewinds.htm
Horse
Latitudes
Between about 30° to 35° north and 30° to 35°
south of the equator lies the region known as the horse latitudes or the
subtropical high. This region of subsiding dry air and high pressure results in
weak winds.
A dhow could get down there , but could not
get back because of the strong current and weak winds .
There might even be traces at Durban of old
Arab expeditions .
The net result was that the whole region was
written off as too dangerous to explore , and nothing worthwhile to exploit
7.Caravels .
This did not affect the Portuguese , because
their caravels were true deep-sea ships . They were not coast-huggers and were
much more efficient in using the winds .
8.The man who did it .
The deep-sea characteristics of the caravel
evolved from the requirements of fishermen in the stormy North Sea .
Henry the Navigator was a crux figure in recent
history .
A sort of combination of old 1969 NASA and
Elon Musk (http://en.wikipedia.org/wiki/SpaceX)
He reshaped the future history of all humans .
The skills involved were politics (money and
influence) , management , navigation , ship design and a spirit of adventure .
A salute to Henry the Navigator !
May he still navigate between the stars ! .
Regards Andre
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