Extensive Recombination Suppression and Genetic Degeneration of a Young ZW Sex Chromosome System in Halfbeak Fish.

ABSTRACT: Sex chromosome systems have evolved independently across the tree of life, at different times in the past, and the evolutionary consequences of lacking recombination in sex-linked regions have been characterized in many old-established systems. However, empirical studies of young sex chromosomes are still scarce, especially in vertebrates. Integrating whole-genome sequencing data of two species of halfbeak fish, Hyporhamphus sajori and Hyporhamphus intermedius, we identified the sex-determining system in H. sajori as female heterogamety, involving a large fully sex-linked ZW region (∼26 Mb) on chromosome 5. The closest relative, H. intermedius, has a small sex-linked region on a different chromosome and shows male heterogamety, suggesting at least one turnover in this fish genus. The H. sa

SUBMITTER: Xing TF 

PROVIDER: S-EPMC12258149 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature