Data from: The evolution of sex determination associated with a chromosomal inversion

Sex determination is a fundamentally important and highly diversified
biological process, yet the mechanisms behind the origin of this diversity
are mostly unknown. Here we suggest that the evolution of sex
determination systems can be driven by a chromosomal inversion. We show
that an XY system evolved recently in particular nine-spined stickleback
(Pungitius pungitius) populations, which arose from ancient hybridization
between two divergent lineages. Our phylogenetic and genetic mapping
analyses indicate that the XY system is formed in a large inversion that
is associated with hybrid sterility between the divergent lineages. We
suggest that a new male-determining gene evolved in the inversion in
response to selection against impaired male fertility in a hybridized
population. Given that inversions are often associated with hybrid
incompatibility in animals and plants, they might frequently contribute to
the diversification of sex determination systems.