title: The XX-XY sex-determination system in Oryzias luzonensis and O. mekongensis revealed by the sex ratio of the progeny of sex-reversed fish.
abstract: The sex-determining gene in Oryzias latipes and O. curvinotus has been proved to be DMY. Although O. curvinotus has the DMY gene on the Y chromosome which is homologous to the Y chromosome of O. latipes, the sex-determining mechanism of other Oryzias fishes has not been identified. In order to uncover the sex-determining mechanism of O. luzonensis and O. mekongensis, which are most closely related species to O. latipes and O. curvinotus, we analyzed the sex ratio of the progeny of sex-reversed fish. We were able to obtain sex-reversed males by the administration of methyltestosterone, and found that these yielded all-female offspring in both species. These results indicate that O. luzonensis and O. mekongensis have the XX-XY sex-determination system.
authors.affiliation: Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan. shamaguc@env.sc.niigata-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamaguchi
authors.forename: Yota
authors.initials: Y
authors.lastname: Toyazaki
authors.forename: Ai
authors.initials: A
authors.lastname: Shinomiya
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sakaizumi
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D006066:Gonads / Q000033:anatomy & histology / Q000187:drug effects; D057850:Hermaphroditic Organisms; D006652:Histological Techniques; D008777:Methyltestosterone / Q000494:pharmacology; D009990:Oryzias / Q000502:physiology*; D010802:Phylogeny; D012730:Sex Chromosomes / Q000502:physiology*; D019849:Sex Determination Processes; D012744:Sex Ratio
chemical_list: D004958:Estradiol; D008777:Methyltestosterone