Seasonal environmental change and sex change in a cnidarian

Here, we investigated the effect of seasonal temperature fluctuations on
the expression of sex-related genes and sex change in the gonochoristic
freshwater cnidarian, brown hydra (Hydra oligactis). Individuals of this
species reproduce clonally throughout much of the year but switch to
sexual reproduction when the temperature decreases in autumn. After sexual
reproduction, some individuals can revert to clonality again. We found
that clonal offspring derived from these individuals had a relatively high
rate of female-to-male transition. The sexual stage was most
differentiated in terms of gene expression, with a large number of genes
involved in cellular differentiation and gametogenesis differentially
expressed between males and females undergoing gamete production, while
asexual individuals belonging to the male and female strains were
transcriptomically nearly identical following sexual reproduction.