Dear list,
Some recent posts have revived - once again, it will not go away -
the Indo-Aryan arrival to India or not issue, this time on the basis
of recent genetic studies. But before making any hasty judgments
either on the basis of such studies or about such studies, I
recommend a careful reading of some of these works first.
First, we have the pioneering work of Sengupta et al.
Polarity and Temporality of High-Resolution Y-Chromosome Distributions
in India Identify Both Indigenous and Exogenous Expansions and Reveal
Minor Genetic Influence of Central Asian Pastoralists
in Am. J. Hum. Genet. 2006;78:202221
http://tinyurl.com/ybugo6
I claim that the above article is methodologically more sophisticated
than
Sanghamitra Sahoo et al.
A prehistory of Indian Y chromosomes: Evaluating demic diffusion scenarios
PNAS January 24, 2006 vol. 103 no. 4 843848
http://www.pnas.org/cgi/reprint/103/4/843
although the latter article is by no means devoid of interest, either.
To see the point of my remark, I recommend reading an article that has
very little to do with India, but was an important step forward in a
methodological sense, namely,
F. Di Giacomo et al.
Y chromosomal haplogroup J as a signature of the post-neolithic
colonization of Europe
Hum. Genet (2004) 115: 357371
DOI 10.1007/s00439-004-1168-9
http://www.familytreedna.com/pdf/HaploJ.pdf
These insights were included in Sengupta et al. but not in Sahoo et
al. Hence my preference for the former.
Finally, an interesting critical comment on Sengupta et al. is
Ancient Indian roots?
by DENISE R CARVALHO-SILVA
TATIANA ZERJAL
CHRIS TYLER-SMITH*
in J. Biosci. 31(1), March 2006, 12, Indian Academy of Sciences
http://www.ias.ac.in/jbiosci
A careful reading of these articles should show, among others, that
(a) on their own, they cannot be used in absolute dating of different
migrations during the relevant time period, (b) progress can be made,
has been made and will be made with respect of relative dating of
migrations that can be identified in the available evidence, (c) some
interesting information is pretty much independent of the timing
problem (as it is the case that some haplogroups that are very
prominent in some areas are completely absent in other areas).
In brief, the studies on contemporary DNA are clearly relevant for the
discussion and it would be unwise to dismiss them. It would be equally
unwise to think that we could simply read out the migrational history
of Holocene period from them.
Cheers, Juha