Posted on 09/23/2009 5:45:59 PM PDT by BGHater
The mixing of two distinct lineages led to most modern-day Indians.
The population of India was founded on two ancient groups that are as genetically distinct from each other as they are from other Asians, according to the largest DNA survey of Indian heritage to date. Nowadays, however, most Indians are a genetic hotchpotch of both ancestries, despite the populous nation's highly stratified social structure.
"All Indians are pretty similar," says Chris Tyler-Smith, a genome researcher at the Wellcome Trust Sanger Institute near Cambridge, UK, who was not involved in the study. "The population subdivision has not had a dominating effect."
India makes up around one-sixth of the world's population, yet the South Asian country has been sorely under-represented in genome-wide studies of human genetic variation. The International HapMap Project, for example, includes populations with African, East Asian and European ancestry — but no Indians. The closest the Human Genome Diversity Cell Line Panel of 51 global populations comes is Pakistan, India's western neighbour. The Indian Genome Variation database was launched in 2003 to fill the gap, but so far the project has studied only 420 DNA-letter differences, called single nucleotide polymorphisms (SNPs), in 75 genes1. Caste divisions
Now, a team led by David Reich of the Broad Institute in Cambridge, Massachusetts, and Lalji Singh of the Centre for Cellular and Molecular Biology in Hyderabad, India, has probed more than 560,000 SNPs across the genomes of 132 Indian individuals from 25 diverse ethnic and tribal groups dotted all over India.
The researchers showed that most Indian populations are genetic admixtures of two ancient, genetically divergent groups, which each contributed around 40-60% of the DNA to most present-day populations. One ancestral lineage — which is genetically similar to Middle Eastern, Central Asian and European populations — was higher in upper-caste individuals and speakers of Indo-European languages such as Hindi, the researchers found. The other lineage was not close to any group outside the subcontinent, and was most common in people indigenous to the Andaman Islands, a remote archipelago in the Bay of Bengal.
The researchers also found that Indian populations were much more highly subdivided than European populations. But whereas European ancestry is mostly carved up by geography, Indian segregation was driven largely by caste. "There are populations that have lived in the same town and same village for thousands of years without exchanging genes," says Reich. Number puzzle
Indian populations, although currently huge in number, were also founded by relatively small bands of individuals, the study suggests. Overall, the picture that emerges is of ancient genetic mixture, says Reich, followed by fragmentation into small, isolated ethnic groups, which were then kept distinct for thousands of years because of limited intermarriage — a practice also known as endogamy.
This genetic evidence refutes the claim that the Indian caste structure was a modern invention of British colonialism, the authors say. "This idea that caste is thousands of years old is a big deal," says Nicole Boivin, an archaeologist who studies South Asian prehistory at the University of Oxford, UK. "To say that endogamy goes back so far, and that genetics shows it, is going to be controversial to many anthropologists." Boivin fears that the study might be 'spun' by politicians seeking to maintain caste structures in India, and she calls on social scientists and geneticists to collaborate on such "highly politicized" issues.
Beyond the study's social repercussions, the low rates of genetic mingling "could have important implications for biomedical studies of Indian populations", notes Sarah Tishkoff, a human geneticist at the University of Pennsylvania in Philadelphia who was not involved in the research. The partitioned population structure will need to be taken into account in any efforts to map disease genes, she says.
The small numbers of founders of each Indian group also have clinical consequences, says Reich. "There will be a lot of recessive diseases in India that will be different in each population and that can be searched for and mapped genetically," he says. "That will be important for health in India."
The evidence that most Indians are genetically alike, even though anthropological data show that Indian groups tend to marry within their own group, is "very puzzling", says Aravinda Chakravarti, a human molecular geneticist at the Johns Hopkins University School of Medicine in Baltimore, Maryland, who wrote an accompanying News & Views article3. For example, Chakravarti notes that the study can't establish a rough date for when the ancient mixing between the two ancestral populations took place. "There are very curious features of the data that are hard to explain," he says, adding: "This is not the end of the story."
* References
1. Indian Genome Variation Consortium J. Genet. 87, 3-20 (2008).
2. Reich, D. et al. Nature 461, 489-494 (2009).
3. Chakravarti, A. Nature 461, 487-488 (2009).
Don’t blame Whitey Ping.
‘One ancestral lineage — which is genetically similar to Middle Eastern, Central Asian and European populations — was higher in upper-caste individuals and speakers of Indo-European languages such as Hindi, the researchers found. The other lineage was not close to any group outside the subcontinent, and was most common in people indigenous to the Andaman Islands, a remote archipelago in the Bay of Bengal.’
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‘This genetic evidence refutes the claim that the Indian caste structure was a modern invention of British colonialism, the authors say. “This idea that caste is thousands of years old is a big deal,”’
No kidding.
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Many moons ago ancient elders smoke em peace pipe with the paleface as mysterious spirits revealed.
I had no idea that anyone blamed the Indian Caste system on the British. But I guess I shouldn’t be surprised.
Every culture I have ever read about has always had some kind of class structure with taboos about crossing the line (at least once the culture rose above the tribal level).
Why would India be different?
Some historians mistakenly believe that railroads were created for the transhipment of people and goods.
The real reason was so that the good people could be born on one side of the tracks, and the bad people on the other.
This is very strange. The indigenous Andamanese are Negritos, who have peppercorn hair and some other traits (like steatopygia) which are remiscent of African Bushmen (Khoi-San). They look very different from any mainland Indians of today.
I think rejection of caste helped Islam become entrenched in Bengal, and is a factor in the spread of Christianity, which is especially strong among the Dalit or “untouchable” caste.
I'd say more in line with Papua. I'm not up to date if there is a DNA link between the two.
Are their memories really that short? Maybe their recorded history ignored the caste system because it was so ubiquitous that it was invisible to those writing their history. It was always there everywhere so why talk about it?
I suppose the British are still hated in India and make a convenient scapegoat to blame their nasty caste system on when they talk to the Liberal Westerners. And of course the Brits a good Liberal reformed Colonial Masters must be self castigating and take the blame willingly.
The Andamanese don’t look much like Papuans at all, nor like most Australian aborigines. Peppercorn hair (as seen in the picture I posted) is found only in Andamanese and African Bushmen. Some think those two groups are the oldest, least changed human groups.
I really can't imagine who would think it was invented by the Brits.
This kind of dovetails with a discovery reported recently about various European and Middle-Eastern Haplogroups. It seems the MOST COMMON haplogroup in Europe is also the most common one in the Middle East EXCEPT, and this is a really big, huge EXCEPT, that haplogroup does not appear among the Sa'ami (Laplanders) in the far North in Europe, nor among Saudi Arabians living on the Arabian peninsula.
Think about it ~ the most common lineage of people in Europe and the Middle East simply disappears in the far North or in the Arabian desert.
Is it because that common type of human simply cannot reproduce itself outside it's narrow "range", or is there a disease, or does Sunlight control their reproductive capacity?
Now we come to India and there are only two main strains, and everybody is part of both, but in different proportions, but what about the other strains who've gone through there? What about the others who were known to have ruled vast areas in India ~ what happened to their genetic imprint?
Again, it's the same sort of pattern you get with Europe and the Middle East which are generally to the North.
Recently there was a report that Middle Easterners living in Sweden had VERY LOW birthrates. Are they trying to survive North of some level of sunlight that they have to have to reproduce?
There are definitely some strange things here that will, eventually, be explained by someone.
That's why its not surprising to find the Islanders don't look all that much like the guys on the Continent.
Papuans tend to have wooly hair somewhat like African Negroes, but not the extremely tightly-wound discrete clusters of hair described by the term “peppercorn.”
John McWhorter sez that the Khoi-San languages are believed to be the oldest surviving language family.
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Thanks BGHater. |
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The article also found that " New data sets...confirm the absence of any Andaman M2 haplotypes among the ethnic populations of India."
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=378623
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