The XX-XY sex-determination system in Oryzias luzonensis and O. mekongensis revealed by the sex ratio of the progeny of sex-reversed fish.
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.
Hamaguchi
Satoshi
S
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan. shamaguc@env.sc.niigata-u.ac.jp
Toyazaki
Yota
Y
Shinomiya
Ai
A
Sakaizumi
Mitsuru
M
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
D004958:Estradiol; D008777:Methyltestosterone