title: The sexually dimorphic on the Y-chromosome gene (sdY) is a conserved male-specific Y-chromosome sequence in many salmonids.
abstract: All salmonid species investigated to date have been characterized with a male heterogametic sex-determination system. However, as these species do not share any Y-chromosome conserved synteny, there remains a debate on whether they share a common master sex-determining gene. In this study, we investigated the extent of conservation and evolution of the rainbow trout (Oncorhynchus mykiss) master sex-determining gene, sdY (sexually dimorphic on the Y-chromosome), in 15 different species of salmonids. We found that the sdY sequence is highly conserved in all salmonids and that sdY is a male-specific Y-chromosome gene in the majority of these species. These findings demonstrate that most salmonids share a conserved sex-determining locus and also strongly suggest that sdY may be this conserved master sex-determining gene. However, in two whitefish species (subfamily Coregoninae), sdY was found both in males and females, suggesting that alternative sex-determination systems may have also evolved in this family. Based on the wide conservation of sdY as a male-specific Y-chromosome gene, efficient and easy molecular sexing techniques can now be developed that will be of great interest for studying these economically and environmentally important species.
authors.affiliation: INRA, UR1037, LPGP, Fish Physiology and Genomics Rennes, France.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Yano
authors.forename: Barbara
authors.initials: B
authors.lastname: Nicol
authors.forename: Elodie
authors.initials: E
authors.lastname: Jouanno
authors.forename: Edwige
authors.initials: E
authors.lastname: Quillet
authors.forename: Alexis
authors.initials: A
authors.lastname: Fostier
authors.forename: René
authors.initials: R
authors.lastname: Guyomard
authors.forename: Yann
authors.initials: Y
authors.lastname: Guiguen
keywords: molecular sexing; salmonids; sdY; sex-determination locus; sex-determining gene