Re: Genetical Study on Indian Castes

From: mkelkar2003
Message: 46957
Date: 2007-01-15

--- In cybalist@yahoogroups.com, "alexandru_mg3" <alexandru_mg3@...>
wrote:
>
> URL:
> http://www.genome.org/cgi/content/full/11/6/994
>
> I cannot check, of course, in anyway if this study is true or false.
>
> But if this study is correct, this suggest that the Native Proto-
> Indians have suffered a kind of "Romanization Process" in the
> past ... : 'learning' the Indo-Aryan language from some Indo-
> Europeans invaders.
>
> Marius


The Bamshad (2001) is methodologically flawed:

Critique of Bamshad:
<http://evolutsioon.ut.ee/publications/Kivisild2003a.pdf>

"In contrast, the majority of the Indian paternal lineages do not
share recent ancestors with eastern Asian population but stem from
haplogroups common to (eastern) European or Western Asian populations.
This finding has recently been interpreted in favor of the classical
Indo-Aryan invasion hypothesis. Here, we show this interpretation is
probably caused by a phylogeographically limited view of the Indian
Y-chromosome pool, amplified because of current inconsistencies in the
interpretation of the temporal scales in the variability of the
non-recombining (NRY). It appears to us that the high variability of
the STR's in the background of NRY variants in India is consistent
with the view of the largely autochthonous pre-Holocene genetic
diversification-a conclusion reached earlier for the Indian maternal
lineages (Kivisilid et al 1990a). "

"However the fact that just the two autochthonous Indian mtDNA
clusters, out of the much larger variety comprise about a thrid of all
maternal lineages of the upper casts of the Dravidian speaking
Telegu's suggest strongly that the origin of the endogamous caste
system should not be traced to a simple model of a putative Indo-Aryan
invasion some 4700 year ago (p. 5)."

Refer to section 7 of proto vedic continuity theory.doc in the files
section for more info. Here is a latest study published in BioEssays
out of Cambridge UK (thanks to Dr. Kalyanaraman for the excertps).

"However, subsequent studies using more representative sample sizes
and, importantly, a higher level of molecular resolution, have
established that, even though Indian and West Eurasian populations
share a common genetic ancestry in late Pleistocene, gene flow into
India during the period of the proposed Aryan invasion has been
minimal. (15,17,18,52) As yet the evidence is equivocal and there is
no genetic signal for a major genetic component associated either with
the spread of Indo-Aryan languages or the caste system within India.
(53), (Chaubey, Metspalu, Kivisilid et. al. 2006)."

BioEssays, Volume 29, Issue 1 , Pages 91 – 100, Published Online: 22
Dec 2006

Peopling of South Asia: investigating the caste-tribe continuum in India

Gyaneshwer Chaubey 1 *, Mait Metspalu 1, Toomas Kivisild 1 2, Richard
Villems 1

1Department of Evolutionary Biology, Institute of Molecular and Cell
Biology, University of Tartu and Estonian Biocentre, Tartu, Estonia
2Leverhulme Centre of Human Evolutionary Studies, The Henry Wellcome
Building, University of Cambridge, UK email: Gyaneshwer Chaubey (
gyanc@...) * Correspondence to Gyaneshwer Chaubey, Department of
Evolutionary Biology, Tartu University and Estonian Biocentre, Riia
23, Tartu, 51010, Estonia.



Abstract


In recent years, mtDNA and Y chromosome studies involving human
populations from South Asia and the rest of the world have revealed
new insights about the peopling of the world by anatomically modern
humans during the late Pleistocene, some 40,000-60,000 years ago, over
the southern coastal route from Africa. Molecular studies and
archaeological record are both largely consistent with autochthonous
differentiation of the genetic structure of the caste and tribal
populations in South Asia. High level of endogamy created by numerous
social boundaries within and between castes and tribes, along with the
influence of several evolutionary forces such as genetic drift,
fragmentation and long-term isolation, has kept the Indian populations
diverse and distant from each other as well as from other continental
populations. This review attempts to summarize recent genetic studies
on Indian caste and tribal populations with the focus on the
information embedded in the socially defined structure of Indian
populations. BioEssays 29: 91-100, 2007


Some excerpts:



…Language shift. Language shift is a cultural process in which an
expanding population changes their language of that of a surrounding
population with only a minor contribution of that population genes.
(25) This process makes for discordance between languages and genes
and that largely hampers the journey of gene with language. An
important process that has shaped the present (spatial) distribution
of languages in South Asia is language shift by indigenous
populations. The Mushar community is one of the best examples of
language shift in India. This community is dispersed mainly in Uttar
Pradesh, Bihar, Jharkhand, Chhattisgarh and Madhya Pradesh and is
known to have spoken the Mundari dialect of the Austro-Asiatic
language family in the recent past. (91) But now they have by and
large adopted Indo-European language from the surrounding populations.
(Mushar literally means mouse eaters Hindi; Mus- 'Mouse',
her-'eater'). Some of them are still hunters and gatherers and
continue to speak the Mundari language. Y chromosome and mtDNA studies
on this population and neighboring Indo-European populations revealed
an almost impermeable genetic boundary between them. This suggests
that the cultural process in India is one where different communities
live side by side, interchanging ideas, foods and goods but not genes.
In certain areas, however, the juxtaposed communities are more or less
independent of one another, kept separate by the hierarchal category
in the caste system...



The ongoing debate . . .



The origin of the Indian caste system and the Indo-Aryan speaking
populations is a matter of intense academic debate with its history
going back to Sir William Jones, who, as a judge in the Presidency of
Bengal, originally reported striking similarities between Sanskrit,
Greek and Latin at the end of the 18 th century. He suggested a common
source for all these languages, while MaxMu¨ ller, another
distinguished orientalist, added, a half century later, the argument
that the Aryans might have migrated to India around 1500 BC. More than
two centuries of extensive interdisciplinary scholarship, in
particular after the 20 th century discovery of the Indus Valley
Civilization and the establishment of the main facts about the
neolithization of South Asia, has greatly widened and enriched the
panorama of the understanding of the peopling of South Asia in the
global context. The study of classical markers put South Asia in
between the populations from West and Southeast Asia. (25)
Furthermore, the 1st principal component, in an analysis of 69 genes
from 42 populations of Asia, explains 17.7% of the variation from
southeast and East Asians into India. (25) More recently, several
genetic studies have added support to this theory. (47–51) Certain
genetic variants were found to be shared among Indian and European
populations. However, subsequent studies using more representative
sample sizes and, importantly, a higher level of molecular resolution,
have established that, even though Indian and West Eurasian
populations share a common genetic ancestry in late Pleistocene, gene
flow into India during the period of the proposed Aryan invasion has
been minimal. (15,17,18,52) As yet the evidence is equivocal and there
is no genetic signal for a major genetic component associated either
with the spread of Indo-Aryan languages or the caste system within
India. (53) The complex structure of the Indian caste system and its
origin is another matter of dispute. The caste society definitely
plays, and may well long have played, an essential role in the genetic
and social structuring of South Asian populations. (54) The haploid
genetic study of castes was, perhaps, started by a chain of papers
relying on the idea of the male-mediated Indo-Aryan invasion, which
supposedly pushed the indigenous Dravidian populations southwards,
and established the Aryans at the top of the caste hierarchy.
(21,55,56) These studies suggested that the caste and tribal groups
differ significantly in haplogroup frequencies. Moreover, caste groups
were found more homogeneous for Y chromosome variation and more
closely related to Central Asian groups than to Indian tribal or any
other Eurasian groups. (56) These results might, however, have been
affected by limited sampling and depth of analysis of Indian tribal
and caste groups because other extended studies have failed to
confirmthe general tribal distinction from the castes. (22) One
important aspect of the Indian caste system, which has a substantial
impact on the inferences that one can make from the caste/tribal
genetic variation, is that the definition of the castes has been
historically fluid. Specifically, the scheduled tribes have been
gradually incorporated into the caste system as scheduled castes. (57)
Yet, another question concerns the initial settlers of India. There
are several studies which state that the Austro-Asiatic tribal groups
represent the first settlers of India most closely. ( 21,58,59) Basuet
al.(21) suggested that haplogroupM2,which is one of the oldest
Indian-specific mtDNA haplogroups,(18) is particularly frequent and
diverseamongAustro-Asiatic speaking tribes of India. This argument
was, however, based on an inaccurate assignment of the tribal samples
into the M2 haplogroup on the basis of hypervariable segment I (HVS I)
motif 16223–16319, which occurs independently in many different
haplogroups. Moreover, because haplogroup M2 is spread across the
borders of Indo-European, Dravidian and Austro- Asiatic language
families and is shared by both tribal and caste communities, (52) it
is problematic to relate the initial Palaeolithic settlers of India on
the basis of certain linguistic affiliations…



Conclusions



Recent progress in the understanding of topology of phylogenetic trees
of the haploid mtDNA and Y-chromosomal genomes combined with
increasingly more detailed phylogeographic mapping of their
crresponding branches globally and in the Indian subcontinent more
specifically, conclusively show that the gene pool of South Asia is
made up essentially from the same basic components as other
non-African gene pools while the local differentiation and long-term
genetic isolation have provided numerous diverse local genetic
variants stemming out from these founders. Most of the Indian-specific
mtDNA haplogroups show coalescent times 40,000–60,000 YBP. Their
virtual absence elsewhere in the world suggests only a limited gene
flow out from the subcontinent over a long time span, probably since
the first in situ expansion phase in Late Pleistocene. Further efforts
are needed to reveal evolutionary, temporal and spatial trajectories
of some Ychromosomal haplogroups, in particular that for haplogroup R,
which is omnipresent in large contiinental areas of Eurasia. This is
particularly important because of an immediately apparent substantial
overlap between the spread of Indo-European languages and NRY
haplogroup R derivatives. In parallel, progress in molecular
resolution of the mtDNA and Y-chromosomal genealogies allows
identification of haplogroups, likely introduced to South Asia at
later stages. A clear subset of mtDNA variants characteristic for East
and Southeast Asia (Fig. 1a) are expectedly most frequent in
northeastern provinces of India among populations speaking
Tibeto-Burman languages. Yet the spectrum is more complex, revealing
recent and, possibly, also earlier language shifts in different
populations, as well as sex-specific admixture patterns.

Several open and complex questions, such as the origin of caste
(gothra) system, the arrival of the major language families and their
spread in South Asia, need to be solved by combining different
disciplines like archaeology, historical linguistics and genetics. In
particular, new promising highthroughput technologies to study
autosomal genetics of South Asian populations might well offer new
insights into unsolved or poorly understood mysteries. The definition
and comparison of present-day patterns of genetic variation in South
Asia not only offer unique insights for a deep study of human
evolutionary history but also provide the necessary population–genetic
background that constitutes an important prerequisite for
understanding the genetics of complex traits.



References (run into 6 pages)