Rewinding the Ratchet: Rare Recombination Locally Rescues Neo-W Degeneration and Generates Plateaus of Sex-Chromosome Divergence.

ABSTRACT: Natural selection is less efficient in the absence of recombination. As a result, nonrecombining sequences, such as sex chromosomes, tend to degenerate over time. Although the outcomes of recombination arrest are typically observed after many millions of generations, recent neo-sex chromosomes can give insight into the early stages of this process. Here, we investigate the evolution of neo-sex chromosomes in the Spanish marbled white butterfly, Melanargia ines, where a Z-autosome fusion has turned the homologous autosome into a nonrecombining neo-W chromosome. We show that these neo-sex chromosomes are likely limited to the Iberian population of M. ines, and that they arose around the time when this population split from North-African populations, around 1.5 million years ago. Recombinatio

SUBMITTER: Decroly T 

PROVIDER: S-EPMC11232697 | biostudies-literature | 2024 Jul

REPOSITORIES: biostudies-literature