Sex Change in Fish

Sexual fate has previously been thought of as an immutable process determined during early embryonic development. However, sexual determination can be dynamic, with antagonistic female and male genetic pathways fighting for dominance. Among vertebrates, many fish display great sexual plasticity and flexibility, with the capability to change sexual phenotype during their lifetime, known as sequential hermaphroditism. Natural sex change involves transformation of behavior, morphology, and neuroendocrine and molecular axes. We review the changes that occur in these biological processes during sex change and show how research into sequential hermaphrodites can extend our knowledge of vertebrate sex determination.