Genetic Evidence of Aryan Invasion into Indian Subcontinent

[Taken from IndiaDivine.org]

Latest genetic research supports the anthropological and historical theory
that the Hindu caste system and the link between the Europeans invasion from
west. Those born into higher castes in India may be more related to Europeans,
while lower castes may be more similar to Asians, the research finds.

The original Hindu caste system is said to have started when Indo-European
nomadic groups called Aryans invaded India about 5000 years ago. They set
themselves as priests and then divided the society they encountered into a
four-part caste system -- Brahmans (priests and teachers), Kshatriyas (rulers
and warriors), Vaisyas (merchants and traders) and Sudras (workers and peasants)
who were born to serve the other three. There also are castes within castes; in
all, there are more than 1,000.

Lowest in the social order are the Harijans or Untouchables. They did all
the dirty work.

Researchers from the United States, the United Kingdom, and India studied
the linkage between the Europeans and high caste in India by DNA. "We've been
working in India, asking questions about the origins of the caste system and
tribal populations," says Dr. Michael Bamshad, an assistant professor at the
University of Utah's Eccles Institute of Human Genetics in Salt Lake City. "We
were also interested in the effects of social forces on biological variations."

Bamshad and his colleagues conducted their research by drawing blood from
eight different populations in the lower, middle and upper castes. They compared
five different types of genetic data, Bamshad says. "Two of those types are
inherited only from your mother -- called mitochondrial data -- and two of those
types are from the Y chromosome, so they come only from the father."

The researchers compared the data to about "750 Africans, Asians and
Europeans and then compared the affinities of the castes of different ranks with
those continental groups," Bamshad says.

The genetic data from the mother shows "some evidence of European
markers," Bamshad reports. The higher the caste, the "higher the frequency of
those European markers," he says.
But genes passed on from the father show a more striking pattern. "When we
looked at father markers, we see that the castes are more similar to Europeans
than Asians, again with the upper classes being closer to Europeans than the
lower classes," Bamshad says.

Though discrimination against the ancient caste system was declared
illegal by bothe Nepalese and Indian government, it still continues as part of
day to day life in both countries.

The findings, which appear in the May issue of Genome Research, support
the historical data showing that India was in part populated by people from
Turkey, the Middle East, the Caucasus or Eastern Europe, Bamshad says.

"And it also suggests that those who migrated from Europe often left their
descendents in the higher castes rather than the lower castes," Bamshad says.
"The evidence from the Y chromosomes shows that it was the men who married into
the upper castes, and it appears that more men than women moved into India, and
that certainly is consistent with the concept of a marauding army."

Bamshad's research falls under the rubric of molecular anthropology, says
Peter Underhill, senior research scientist in genetics at Stanford University.
"The main thrust of this research project is to better understand the Indian
population, where it came from, how it developed."

"This research, which attempts to correlate genetics with the historical
record, provides good genetic evidence, and such correlations are reassuring,"
Underhill says. "What's particularly nice about this paper is that it doesn't
emphasize one slice of the genome. It weaves in genetics from both men and
women."

While Bamshad's research has no direct relevance, "it would be of some
interest to medical genetic studies. It's another piece of the puzzle that might
help scientists understand certain traits within the Indian population,"
Underhill says.

The main feature of Indian society, seen at its strongest in the rural areas, is
caste. A caste is a collection of people who share similar cultural and
religious values and practices. Members within a caste generally marry among
themselves; intercaste marriages are a cultural taboo. These social regulations
governing the institution of marriage have resulted in a substructuring of the
Indian gene pool. There are also elaborate social regulations of avoidance of
marriages within castes, and thus there is genomic substructuring even within a
caste.

The origins of the castes in India remain an enigma. Many castes are known to
have tribal origins, as evidenced from various totemic features that manifest
themselves in these caste groups (Kosambi 1964). The caste system in northern
India may have developed as a class structure from within tribes: As agriculture
spread from the Indus River valley to the Gangetic basin, knowledge and
ownership of the means of food production may have created hierarchical
divisions within tribal societies (Kosambi 1964). Karve (1961) has also argued
that "something very like castes were in India" even before Aryan speakers
entered India.

The Aryan world comprised three classes (varnas): priests, nobles, and
commoners. Aryans as the conquering people possibly placed their three classes
on the indigenous Indian society. The varna organization is hierarchical.
Initially, the system had names for two ranks, Brahma (Brahmin) and Kshatra
(Kshatriya), Brahmin being of a socially higher rank than Kshatriya. The third
rank was made up of Vis, that is, all the subjects. To this society, a fourth
rank was added: Shudra, who had no rights to Aryan ritual. In southern India,
the menial workers, the so-called "untouchables", were placed in a new varna,
Panchama (meaning fifth). It is conceivable that the Aryan speakers had greater
contact, including genetic admixture, with the Brahmins, who were professionally
the torchbearers and promoters of Aryan rituals. The Aryan contact should have
been progressively less as one descended the varna ladder. The genetic
expectation, therefore, is that the proportions of those genes (or genomic
features, such as haplotypes or haplogroups) that "characterized" the Aryan
speakers should progressively decline from the highest varna to the lowest and a
reverse trend should be observed with respect to those genes that
"characterized" the indigenous Indians.

Although some previous studies have sought to test this expectation, the
observed trends were equivocal. The primary reason was the lack of data on a
large uniform set of markers from populations of India and central/west Asia
(the region from which the Aryans speakers who entered India originated). The
study by Bamshad et al. (2001), who have also sought to test the above
expectation, is clearly a landmark. Using a very large battery of genomic
markers and DNA sequences, spanning autosomal, mitochondrial, and Y-chromosomal
genomic regions, they have shown that the observed trend of genetic admixture
estimated from castes belonging to different varnas is congruent with
expectations. This trend was observed in each of the three data subsets. The
only exception was in respect of mtDNA restriction site haplotypes, which was
also noted in a recent study conducted by us (Roychoudhury et al. 2000).
However, after combining these haplotype data with DNA sequence data, Bamshad
and colleagues were able to capture the expected trend. Thus, this study not
only provides a wonderful genomic view of the castes and of their origins, but
also underscores the need for careful statistical analysis of genomic data for
drawing appropriate inferences.

The use of "upper", "middle", and "lower" to designate caste hierarchy is much
more recent than the use of varna. Whereas varnas are traditionally defined,
different anthropologists have used different definitions of upper, middle, and
lower castes, in terms of the castes that they included in each of these
clusters. Sometimes these differences in definitions have stemmed from
socio-cultural similarities or differences as noted or perceived by different
anthropologists, and sometimes ranked caste-cluster compositions were altered
for convenience, such as pooling to adjust for small sample sizes. As noted
earlier, in studies such as Bamshad et al.'s, the most appropriate
classification is by varna. As the reader will note, the authors have analyzed
their data using different compositions of hierarchical caste-clusters and have
obtained homologous results. However, it needs to be emphasized that traditional
varna system is the only unequivocally accepted hierarchical system. In studies
pertaining to the origins of castes, one is liable to draw incorrect inferences
by including castes belonging to different varnas in the same ranked cluster.

Bamshad et al. have chosen to study caste populations drawn from a restricted
geographical region of India. They have rightly emphasized the need to replicate
their findings. This is absolutely essential because, as Karve (1961) has noted,
"it is not generally realized that the caste society in a sense was a very
elastic society." Indeed, a caste bearing the same name may have very different
origins in different geographical regions. There are examples in which a tribe
dispersed over a large geographical region, took up different occupations in
different sub-regions, and "fitted" itself into the caste hierarchy on different
rungs. Karve's work has also indicated that each of the different Brahmin castes
(Chitpavan, Sarasvat, etc.) in Maharashtra probably has a different origin.
Thus, the origin of caste populations may not be uniform over the entire India
geographical space, and it is crucial to undertake studies to replicate Bamshad
et al.'s findings. Finally, I would also like to suggest that in future studies
bearing on the origins of the Indian castes, it would be a good idea to include
tribal populations inhabiting the same region along with the caste populations.

REFERENCES


a.. Bamshad, M., Kivisild, T., Watkins, W.S., Dixon, M.E., Ricker, C.E., Rao,
B.B., Naidu, J.M., Prasad, B.V.R., Reddy, P.G., Rasanayagam, A. 2001. Genome
Res. 11: 994-1004[Abstract/Free Full Text].
b.. Karve, I. 1961. Hindu Society - An Interpretation. Deshmukh Prakashan,
Poona.
c.. Kosambi, D.D. 1964. The Culture and Civilisation of Ancient India in
Historical Outline, 1991 Reprint. Vikas Publishing House Pvt. Ltd., New Delhi.
d.. Roychoudhury, S., Roy, S., Dey, B., Chakraborty, M., Roy, M., Roy, B.,
Ramesh, A., Prabhakaran, N., Usha Rani, M.V., Vishwanathan, H. 2000. Curr. Sci.
79: 1182-1192.