Sex differences in the expression of GH/IGF axis genes underlie sexual size dimorphism in the yellow catfish（Pelteobagrus fulvidraco）

Dear Editors,Sexual dimorphism is the systematic difference in size,shape,color,physiology,and behavior,between male and female individuals of the same species（Mei and Gui,2015）.Some studies have indicated that the traits of sexual dimorphism in vertebrates are the consequences of sex-biased gene expression and are controlled by multiple critical genes during growth and development（Williams and Carroll,2009）.However,the exact molecular mechanism underlying sexual dimorphism remains unclear.