PRDM9 is widely conserved across vertebrates yet has been lost numerous times, as has its role in directing meiotic recombination.

A fish-derived bile salt was shown to act as interspecific infochemical, inducing the widespread predator avoidance behavior diel vertical migration at picomolar concentrations in freshwater zooplankton of the genus Daphnia.

Tracing the evolution of an old master sex determination gene reveals a diversity of sex determination transitions, including a complete Y chromosome loss, among an old teleost order (Esociformes).