Tropical Biosphere Research Center, Sesoko Station, University of the Ryukyus, Motobu, Japan.
Sex Dev. 2013;7(1-3):115-25. doi: 10.1159/000342009. Epub 2012 Aug 31.
Among vertebrates, fishes show an exceptional range of reproductive strategies regarding the expression of their sexuality. Fish sexualities were categorized into gonochorism, synchronous/sequential hermaphrodite, or unisexual reproduction. In gonochoristic fishes, sex is determined genetically or by environmental factors. After sex determination, the gonads are differentiated into ovary or testis, with the sex remaining fixed for the entire life cycle. In contrast, some sequential hermaphrodite fishes can change their sex from male to female (protandrous), female to male (protogynous), or serially (bi-directional sex change) in their life cycle. In many cases, sex change is cued by social factors such as the disappearance of a male or female from a group. This unique diversity in fishes provides an ideal animal model to investigate sex determination and differentiation in vertebrates. This review first discusses genetic-orientated sex determination mechanisms. Then, we address the gonadal sex differentiation process in a gonochoristic fish, using an example of the Nile tilapia. Finally, we discuss various types of sex change that occur in hermaphrodite fishes.
在脊椎动物中，鱼类在性别表达方面表现出了非凡的生殖策略多样性。鱼类的性别可以分为雌雄同体、同步/顺序雌雄同体或单性生殖。在雌雄同体的鱼类中，性别是由遗传或环境因素决定的。性别决定后，性腺分化为卵巢或精巢，其性别在整个生命周期中保持固定。相比之下，一些顺序雌雄同体的鱼类在其生命周期中可以从雄性变为雌性（雄性先熟）、从雌性变为雄性（雌性先熟）或连续（双向性别转换）。在许多情况下，性别的改变是由社会因素引起的，例如群体中雄性或雌性的消失。鱼类这种独特的多样性为研究脊椎动物的性别决定和分化提供了理想的动物模型。本综述首先讨论了基于遗传的性别决定机制。然后，我们以尼罗罗非鱼为例，讨论了雌雄同体鱼类的性腺性别分化过程。最后，我们讨论了雌雄同体鱼类中发生的各种类型的性别转换。
