Opposing patterns of intraspecific and interspecific differentiation in sex chromosomes and autosomes.

摘要: Linking intraspecific and interspecific divergence is an important challenge in speciation research. X chromosomes are expected to evolve faster than autosomes disproportionately contribute reproductive barriers, comparing genetic variation on autosomal markers within between species can elucidate evolutionary processes that shape genome variation. We performed RADseq a 16 population transect of two closely related Australian cricket species, Teleogryllus commodus T. oceanicus, covering allopatry sympatry. This classic study system for sexual selection provides rare exception Haldane's rule, as hybrid females sterile. found no evidence recent introgression, despite the fact coexist overlapping habitats wild interbreed laboratory. Putative X-linked loci showed greater differentiation compared with loci. However, was unexpectedly lower markers, relative X-to-autosomal diversity inflated above neutral expectations. Populations both genomic signatures expansions, but these were not strong enough account X/A diversity. Instead, most excess polymorphism could better be explained by sex-biased increase effective size X, such strength among males. Taken together, opposing patterns at versus implicate role sex-linked genes maintaining boundaries this system.