Measures of linkage disequilibrium among neighbouring SNPs indicate asymmetries across the house mouse hybrid zone
Abstract
Theory predicts that naturally occurring hybrid zones between genetically distinct taxa can move over space and time as a result of selection and/or demographic processes. However, direct observations of hybrid zone movement are difficult to make unless the zone is moving rapidly.
Here, evidence for movement in the house mouse Mus musculus domesticus x M. m. musculus hybrid zone is provided using measures of LD and haplotype structure among neighbouring SNP markers from across the genome. Local populations of mice across two transects in Germany and the Czech Republic were sampled, and a total of 1301 mice were genotyped at 1401 markers from the nuclear genome.
Empirical measures of LD provide evidence for extinction and (re)colonization in single populations and, together with simulations, suggest hybrid zone movement because of either geography-dependent asymmetrical dispersal or selection favouring one subspecies over the other.