Saturday, September 22, 2012
Namakw Nomadic Dome(s)tic
A possible tie-in
kusa/kosa/kosei cf khoi-khoi-san of namakwa/kalahari SW Africa
"noma/nomatka/nomatzinco(Nauatl)=forever" cf namakwa/nomadic/dome(s)tic
The Khoe-San people of southern Africa, who speak a language based on
clicking sounds, are descendants of the most ancient genetic split
found yet in living humans, finds an international group of
The results also reveal some of the evolutionary changes that helped
give rise to modern humanity.
Anatomically modern humans (us), evolved about 200,000 years ago in
Africa. Differences between people living today and our evolutionary
relatives include much less pronounced eyebrow ridges and larger
Much remains uncertain about how modern humans originated in Africa's
cradle of humanity. For instance, researchers had long thought humans
arose in eastern Africa, but recent studies hint at roots in southern
Africa. [Image Gallery: Our Closest Human Ancestor]
To help uncover the origins of humanity, scientists analyzed genetic
variations across 220 individuals from 11 different populations in
southern Africa to explore their relationships and commonalities.
Approximately 2.3 million DNA variations were analyzed per person.
The investigators found the earliest diversification event in the
history of all humans occurred about 100,000 years ago. That is well
before modern humans migrated out of Africa and about twice as old as
the divergences of central African Pygmies and East African
hunter-gatherers and from other African groups, said researcher Carina
Schlebusch at Uppsala University in Sweden.
The descendants of this split are the Khoe-San people, the two
hunter-gatherer ethnic groups who are known for speaking with clicks
and share many other traits. Historically, the Khoe were pastoralists,
employing domesticated sheep and cattle, while the San were
It remains uncertain what exactly made the Khoe-San diverge and become
genetically isolated from other African groups.Still, "the African
continent is large, and there are geographic barriers to gene
flow,"researcher Mattias Jakobsson, also of Uppsala University, told
"Another factor that might play a role in the isolation of African
populations is also the cycling of the ice ages," Schlebusch told
LiveScience."In Africa, you get stages of really arid conditions with
ice ages and we see population contractions."
The scientists aren't sure the purposes of the genetic variations that
set the Khoe-San apart. The extent to which each gene variation shapes
what people are like physically "is very, very hard to understand at
this stage," researcher Himla Soodyall at the University of the
Witwatersrand in South Africa told LiveScience.
Rise of modern humans
The researchers also identified genetic variations that emerged before
this split between the Khoe-San and other groups, adaptations linked
to the rise of modern humans as a whole. These appear linked with
skeletal development, such as bone and cartilage growth, as well as
immune system and brain cell function.
"There's one gene where if you have mutations in that gene, you get
heavy eyebrow ridges and rib cages that look like something that could
potentially be Neanderthal or archaic human," Jakobsson told
LiveScience. This finding suggests that further analysis of these
African groups "will help us understand the emergence of anatomically
Instead of pinpointing a single location from which modern humans
arose, the genetic analysis revealed "different parts of Africa show
up as potentially being the origin of anatomically modern humans,"
Jakobsson said. That suggests many different groups contributed to the
gene pool "that then later on became anatomically modern humans," he
The research also yielded insights on how pastoralism first spread to
southern Africa. Among the Nama, a pastoralist Khoe group, the
scientists found a small but very distinct genetic component that is
shared with east Africans — for instance, the cattle-herding Maasai.
"We postulate that this east African component was introduced by east
African groups that brought pastoralist practices to southern Africa,"
In addition, the northern San populations differed from the southern
San in terms of their immune systems. "We know the southern San
populations had more contact with Bantu-speaking individuals and also
incoming colonists that colonized South Africa in the 1600s, so it
might be that the southern San populations were exposed to more novel
diseases than northern San populations which were more isolated,"
at 11:56 AM