http://vetinari.sitesled.com/india.pdf
"Our reappraisal indicates that pre Holocene and Holocene-era-not
Indo-European expansion have shaped the distinctive South Asian Y
chromosome landscape (Sengupta et. Al. 2005, Abstract)."
"In other words, there is no evidence whatsoever to conclude that
Central Asia has been necessarily the recent donor and NOT THE
RECEPTOR of the R1a lineages (Sengupta et. Al, 2005, p. 17, emphasis
added)."
http://www.pnas.org/cgi/content/abstract/0507714103v1
(Thanks to P. Manansala for the complete article).
"The sharing of some Y-chromosomal haplogroups between Indian and
Central Asian populations is most parsimoniously explained by a deep,
common ancestry between the two regions, with diffusion of some
Indian-specific lineages northward (abstract)."
"Rather the high incidence of R1* and R1a throughout Central Asian and
East European populations (without R2 and R* in most cases) is more
parsimoniously explained by gene flow in the opposite direction
possibly with an early founder effect in South or West Asia (p. 4)."
"A pre-Neolithic chronology for the origins of Indian Y chromosomes is
also supported by the lack of a clear delineation between DR
(Dravidian) and IE (Indo-European) speakers (p. 5, parenthesis added)."
posted by M. Kelkar