Varaince of R1b is greatest towards East. R2 is of course in East. And R1a Chenchus are not just any population, they are a relict population which subsequently expanded in the subcontinent.
http://1.bp.blogspot.com/_lvVZ6C97yUo/Sp-R...equency+map.jpg
http://1.bp.blogspot.com/_lvVZ6C97yUo/Sp-R...equency+map.jpg

