Another study:
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)."
M. Kelkar