[Incomplete congruence between morphobiological characters and sex-specific molecular markers in Pacific salmons: 1. Analysis of discrepancy in five species of the genus Oncorhynchus].

The congruence between molecular markers, identifying the presence of the Y chromosome, and secondary sexual characters was examined in Asian populations of five Pacific salmon species: pink salmon (Oncorhynchus gorbuscha), chum salmon (O. keta), sockeye salmon (O. nerka), chinook salmon (O. tschawytsha), and sima (O. masou). It was demonstrated that in all species examined, the presence or absence of sex-specific molecular markers was to a considerable degree congruent with secondary sexual characters, but in some cases, an incongruence was found. These findings suggested that the mechanism underlying this phenomenon was similar or identical in all species examined. Possible genetic and physiological explanations of this phenomenon are discussed.