Fine-scale cultural variation reinforces genetic structure in England

Abstract

Genes and languages both maintain signatures of human history. The evolution of genetics and of culture both have features that can track population movements and demographic history. Further, cultural traits may themselves impact these movements and demography. In particular, while speaking a different language appears to act as a barrier to gene flow, it is not clear whether more subtle dialect-level linguistic differences within a language can influence mating preferences and thus affect genetic population structure. We examine the strength of cultural barriers and of association within England using the spatial similarities between rates of linguistic and genetic change. We find that genes and dialect markers have similar spatial distributions at all geographic scales, though these similarities are more pronounced at larger scales. This covariation, in the absence of geographic barriers to coordinate linguistic and genetic differentiation, suggests that some cultural boundaries have maintained genetic population structure in England.