Postcopulatory sexual selection reduces Z-linked genetic variation and might contribute to the large Z effect in passerine birds.

ABSTRACT: The X and Z sex chromosomes play a disproportionately large role in intrinsic postzygotic isolation. The underlying mechanisms of this large X/Z effect are, however, still poorly understood. Here we tested whether faster rates of molecular evolution caused by more intense positive selection or genetic drift on the Z chromosome could contribute to the large Z effect in two closely related passerine birds, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (L. luscinia). We found that the two species differ in patterns of molecular evolution on the Z chromosome. The Z chromosome of L. megarhynchos showed lower levels of within-species polymorphism and an excess of non-synonymous polymorphisms relative to non-synonymous substitutions. This is consistent with increased l

SUBMITTER: Janousek V 

PROVIDER: S-EPMC6461759 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature