Allelic variation and duplication of the dmrt1 were associated with sex chromosome turnover in three representative Scatophagidae fish species

Abstract With known candidate sex-determining genes (male-specific dmrt1Ys), fish species of the family Scatophagidae are good models for studying sex chromosome evolution. Here, we analyzed sex chromosome turnover events in three representative fish species from two genera of the family Scatophagidae that have diverged 12.8 million years ago (Mya). Scatophagus argus and Sc. tetracanthus possess dmrt1Ys that arose from allelic variation before they diverged 7.2 Mya, and their loci are truncated dmrt1ΔX. The Y chromosome (Chr1) of Sc. tetracanthus is the result of the fusion of the original Y chromosome (Chr4) with an autosome (Chr13). The Selenotoca multifasciata dmrt1Y arose from a duplication of dmrt1 on Chr4 and then translocated to the new Y chromosome (Chr18). The different evolutionary trajectories of the dmrt1Ys were accompanied by sex chromosome turnover in these three species. The sex chromosomes of the Scatophagidae family have evolved rapidly, but not randomly.