So many people talking about nonsense here.
How on earth Pakistanis are different "Genetically" from other south Asians.
It is scientifically proven that every south Asians share similar ancestry.Bengalis are 85% similar to Pakistanis, the 15% difference is due to east Asian admixture in bengalis.
I agree Pakistanis on average are taller and fairer than rest of South Asia, but they are not a different race, even Afghans share same ancestry with rest of south Asia.
Few days ago my cousin(Bengali) was stopped by a new Pakistani immigrant for some help, The pakistani guy started to talk in urdu, and he thought my cousin was a Pathan, which make sense as my cousin was 6'3, hook nosed,robust and fair skinned, compared to the pakistani guy, who was short and dark.My cousin definitely has some east Asian Dna which the Pakistani guy doesnt have, yet my cousin doesnt have any east Asian feauture.
Stereotyping people based on phenotype is very inappropriate.
The first two people that migrated to south Asia was ANI(Caucasoid) and ASI(Australoid-Caucasoid with some archaic Mongoloid) and mixture of these two ancestral population comprises atleast 70% of modern south Asian genetics, later Pakistanis, North Indian and Bangladeshis got some European related DNA from proto Indo Aryans plus Bengalis got some east Asians from Austroasiatic and Tibeto Burman tribes.South Indian got extra ASI.