Sexual Size Dimorphism, Sex Determination, and Sex Control in Yellow Catfish

Abstract

Yellow catfish (Pelteobagrus fulvidraco) is an important freshwater species for aquaculture production in China and East Asia. Sexual size dimorphism in yellow catfish has been observed, since the growth rate in males is much higher than that in females. Thus, production of all-male yellow catfish has significant commercial value in aquaculture. In this chapter, we will introduce the development and improvement of sex chromosome-linked markers in yellow catfish, and describe how all-male populations were created by crossing XX females with YY supermales that were produced by sex control technique assisted by sex chromosome-linked markers. Meanwhile, yellow catfish will be a promising research model for studying the genetic basis of fish sex determination and sexual size dimorphism. We review recent research literatures on morphological differentiation during gonad development, sex-biased expression of mRNA and miRNAs in the XX ovary, XY and YY testis of yellow catfish, and the relationship between gene expression and sexual size dimorphism. We present evidence that sex determination in yellow catfish is controlled by both genetic and environmental factors, and that sexual size dimorphism in yellow catfish is probably caused by the sex difference in expression of ghrelin and GHSR, which regulate feeding and food intake, and GH/IGF signaling, which controls body growth. Finally, we present our perspectives on study of sex determination and sex control breeding in yellow catfish and some other fish species with XY sex-determining system and sexual size dimorphism.