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Permalink Reply by doone on September 20, 2012 at 11:41pm

Khoe-San peoples diverged before 'out-of-Africa' migration of modern humans

http://www.sciencedaily.com/releases/2012/09/120920141139.htm

September 20, 2012

ScienceDaily (Sep. 20, 2012) — Genetically, culturally and ethically the Khoe-San have something special to add to this world.  The largest genomic study ever conducted among Khoe and San groups reveals that these groups from southern Africa are descendants of the earliest diversification event in the history of all humans -- some 100,000 years ago, well before the 'out-of-Africa' migration of modern humans.

Some 220 individuals from different regions in southern Africa participated in the research that led to the analysis of around 2.3 million DNA variants per individual -- the biggest ever.

The research was conducted by a group of international scientists, including Professor Himla Soodyall from the Human Genomic Diversity and Disease Research Unit in the Health Faculty at the University of the Witwatersrand in Johannesburg.

Entitled Genomic variation in seven Khoe-San groups reveals adaptation and complex African history, the study has been selected for early online publishing in the scientific journal, Science, on September 20, 2012.

"The deepest divergence of all living people occurred some 100,000 years ago, 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," says lead author Dr Carina Schlebusch, a Wits University PhD-graduate now conducting post-doctoral research at Uppsala University in Sweden.

Soodyall, from National Health Laboratory Services in South Africa, has a long standing relationship with Khoe and San communities and said that the findings are a "phenomenal tribute to the indigenous Khoe and San people of southern Africa, and through this magnificent collaboration, we have given the peoples of Africa an opportunity to reclaim their place in the history of the world."

Besides the publication of the study, the authors will also be visiting the San groups in the Kalahari, in the Askam area in South Africa on the 24th of September 2012 for the country's Heritage Day celebrations. "We are excited that together with some of our colleagues from Uppsala University, we will be able to join in the celebrations with the San groups in the Kalahari who participated in our research and to acknowledge their contribution in making our research possible."

The researchers are now making the genome-wide data freely available: "Genetic information is getting more and more important for medical purposes. In addition to illuminating their history, we hope that this study is a step towards Khoe and San groups also being a part of that revolution," says Schlebusch. Another author, Professor Mike de Jongh from University of South Africa adds, "It is important for us to communicate with the participants prior to the genetic studies, to inform individuals about the nature of our research, and to also go back to not only to share the results with them, but also to explain the significance of the data for recapturing their heritage, to them."

According to Assistant-Professor Mattias Jakobsson from Uppsala University, these deep divergences among African populations have important implications and consequences when the history of all humankind is deciphered.

The deep structure and patterns of genetic variation suggest a complex population history of the peoples of Africa. "The human population has been structured for a long time," says Jakobsson, "and it is possible that modern humans emerged from a non-homogeneous group."

The study also found surprising stratification among Khoe-San groups. For example, the researchers estimate that the San populations from northern Namibia and Angola separated from the Khoe and San populations living in South Africa as early as 25,000 -- 40,000 years ago.

"There is astonishing ethnic diversity among the Khoe-San group, and we were able to see many aspects of the colorful history that gave rise to this diversity in their DNA," said Schlebusch.

The study further indicates how pastoralism first spread to southern Africa in combination with the Khoe culture. From archaeological and ethnographic studies it has been suggested that pastoralism was introduced to the Khoe in southern Africa before the arrival of Bantu-speaking farmers, but it has been unclear if this event had any genetic impact.

The Nama, a pastoralist Khoe group from Namibia showed great similarity to 'southern' San groups. "However, we found a small but very distinct genetic component that is shared with East Africans in this group, which may be the result of shared ancestry associated with pastoral communities from East Africa," says Schlebusch.

With the genetic data the researchers could see that the Khoe pastoralists originate from a Southern San group that adopted pastoralism with genetic contributions from an East African group -- a group that would have been the first to bring pastoralist practices to southern Africa.

The study also revealed evidence of local adaptation in different Khoe and San groups. For example, the researchers found that there was evidence for selection in genes involved in muscle function, immune response, and UV-light protection in local Khoe and San groups. These could be traits linked with adaptations to the challenging environments in which the ancestors of present-day San and Khoe were exposed to that have been retained in the gene pool of local groups.

The researchers also looked for signals across the genome of ancient adaptations that happened before the historical separation of the Khoe-San lineage from other humans. "Although all humans today carry similar variants in these genes, the early divergence between Khoe-San and other human groups allowed us to zoom-in on genes that have been fast-evolving in the ancestors of all of us living on the planet today," said Pontus Skoglund from Uppsala University.

Among the strongest candidates were genes involved in skeletal development that may have been crucial in determining the characteristics of anatomically modern humans.

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The above story is reprinted from materials provided by University of the Witwatersrand, via EurekAlert!, a service of AAAS.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

1. Carina M. Schlebusch, Pontus Skoglund, Per Sjödin, Lucie M. Gattepaille, Dena Hernandez, Flora Jay, Sen Li, Michael De Jongh, Andrew Singleton, Michael G. B. Blum, Himla Soodyall, and Mattias Jakobsson. Genomic Variation in Seven Khoe-San Groups Reveals Adaptation and Complex African History. Science, 20 September 2012 DOI: 10.1126/science.1227721

Permalink Reply by Davy on September 21, 2012 at 5:01pm

Studying Languages is a fascinating hobby especially English.

Permalink Reply by Marianne on September 21, 2012 at 8:49am

I believe language is evolving at a very fast rate due to more intercommunication first between the same language (think of how many new words each year are accepted in the current dictionnary).  Also there is the phenomenon of texting which I do not know where it will lead language wise.

I also think that geographic isloation tend to keepthe language from evolving.

I'm sorry but I didn't quite understand the chart;  to me, it seemto refer to languages that are spoken by a very small minority of people.

Permalink Reply by Davy on September 21, 2012 at 4:36pm

This reminds me of a little snippet I read in Readers Digest many moons ago now. It was about a Danish farmer ( I think) whose farm has been in the family for about three hundred years. He said that had his first forebear had told a joke that he passed on to his son, then on to his son down through years to him. That there would be laughter down through the years but his first forebear would not understand him because of the change in language over that time. 

The chart sets out the language families not the actual languages spoken because Australia has more than one native language but all the Koori languages are related. Just like the Slavic family of languages ( Russian, Ukrainian, Polish etc) are although they sound similar are different Ukrainian has words that are pronounced the same as Polish words. While at the same time Ukraine has words that are similar to Russian words. But the verb subject object arrangement for Ukrainian is the same as English whilst Russian is not as it has a different arrangement. 

Permalink Reply by Davy on September 21, 2012 at 4:55pm

Marianne. Wikipedia has a reasonable good entry on the history of the English language 

http://en.wikipedia.org/wiki/History_of_the_English_language#Old_En...

Evolution of a language is more than just adding words to your lexicon but also the pronunciation, the sentence structure and quite a few other parts of the language as well. 

Adding words from other languages is referred to horizontal evolution while they were also talking about the vertical evolution which is the changes made by the users of the language. 

The article above helps to explain what I am saying. 

Hope I haven't confused you more about languages.

Permalink Reply by Empetrum Nigrum on September 22, 2012 at 7:12am

I would be extremely skeptical of this. This sounds like glottochronology is trying to make a come back. Languages tend, over vast amounts of time, to cycle between various stages, with each stage requiring a huge amount of new features/innovation. For example, the fact that both Indo-European languages and Uralic languages share a nominative-accusative noun case system is most likely both due to areal influence and is perhaps due to a random change from ergative-absolutive (the other common system) to nom-acc in Indo-European languages (some of the older languages of the branch still exhibit certain ergative qualities and it has been debated that the earliest forms of Proto-Indo-European might have been ergative).

This map is also especially doubtful because of how closely related the north-caucasian languages (for example Ubykh, an extinct language having the largest number of consonants in any language, excluding click-languages) would be to the australian languages (?), which themselves form a number of completely unrelated families amongst themselves.

So I think that linking such divergent and otherwise entirely unrelated language families based on genetics and shared 'stable' features is really just an indication of popular/likely evolutionary paths in language in general.