Global patterns in human mitochondrial DNA and Y-chromosome variation caused by spatial instability of the local cultural processes

Because of the widespread phenomenon of patrilocality, it is
hypothesized that Y-chromosome variants tend to be more localized
geographically than those of mitochondrial DNA ( mtDNA). Empirical
evidence confirmatory to this hypothesis was subsequently provided
among certain patrilocal and matrilocal groups of Thailand, which
conforms to the isolation by distance mode of gene diffusion.
However, we expect intuitively that the patterns of genetic
variability may not be consistent with the above hypothesis among
populations with different social norms governing the institution
of marriage, particularly among those that adhere to strict
endogamy rules. We test the universality of this hypothesis by
analyzing Y-chromosome and mtDNA data in three different sets of
Indian populations that follow endogamy rules to varying degrees.
Our analysis of the Indian patrilocal and the matrilocal groups is
not confirmatory to the sex- specific variation observed among the
tribes of Thailand. Our results indicate spatial instability of the
impact of different cultural processes on the genetic variability,
resulting in the lack of universality of the hypothesized pattern
of greater Y-chromosome variation when compared to that of mtDNA
among the patrilocal populations.