Inheritance Studies Implicate a Genetic Mechanism for Apparent Sex Reversal in Chinook Salmon

• DOI: 10.1577/t04-208.1
• Publication Date: 2005-08-10T14:10:11Z
• Authors: Kevin S. Williamson; Bernie May
• Keywords: Chinook wind; Sexual Differentiation

Abstract The apparent increase in altered sexual differentiation Pacific salmon Oncorhynchus spp. is a growing concern. Previous studies suggest that incongruence between genetic and phenotypic sex Chinook O. tshawytscha may be result of through exposure to endocrine‐disrupting chemicals (EDCs). Artificial crosses genotypically normal salmon, or males sex‐reversed (XY females), were performed test the validity OtY1 growth hormone pseudogene ( GH Ψ) markers as indicators fall‐run salmon. offspring produced genotyped with Y‐chromosome‐specific dissected observe gonad morphology. results breeding experiments indicate approximately half female XY females have male genotype according both Y‐chromosome markers. These refute an earlier hypothesis females) are caused by EDC exposure. Instead, either Ψ recombined Y X chromosomes autosome, mutation has inactivated sex‐determining region chromosome. In none 2,384 evaluated did contradict one another single individual. present evidence appear not diagnostic for Central Valley California.