title: The novel mutant scl of the medaka fish, Oryzias latipes, shows no secondary sex characters.
abstract: A new mutant that has neither male nor female secondary sex characters was found in the medaka, Oryzias latipes. Both XX and XY mature mutants had gonads with many spermatozoa, but spawning did not occur when the mutants were paired with normal males or normal females. F1 progeny were successfully obtained by artificial insemination using unfertilized eggs from wild-type females and spermatozoa of the XY mutant. The mutant phenotype did not occur in the F1 progeny from this cross. Incrossing among the F1 progeny produced 17 mutant offspring out of 68 progeny (25%), demonstrating that the mutant phenotype is caused by a single recessive mutation. This mutant was named scl (sex character-less). Because papillary processes, a male secondary sex character, were induced in the XY mutants by androgen administration, it seems that the androgen receptor is functioning normally. We found a loss-of-function type mutation in the P450c17 gene of the mutant; this gene encodes a steroidogenic enzyme required for the production of estrogen and androgen. The scl phenotype was completely linked to the mutant genotype of P450c17, strongly suggesting that mutation at the P450c17 locus is responsible for the scl mutant phenotype.
authors.affiliation: Department of Environmental Science, Faculty of Science, Niigata University, Ikarashi, Niigata, Japan. satochu@env.sc.niigata-u.ac.jp
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sato
authors.forename: Aya
authors.initials: A
authors.lastname: Suzuki
authors.forename: Naoki
authors.initials: N
authors.lastname: Shibata
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sakaizumi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamaguchi
mesh_terms: D000728:Androgens / Q000378:metabolism; D000818:Animals; D005260:Female; D005786:Gene Expression Regulation; D005838:Genotype; D007621:Karyotyping; D008297:Male; D009154:Mutation; D009990:Oryzias / Q000235:genetics* / Q000502:physiology*; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism; D013737:Testis / Q000502:physiology; D013997:Time Factors
chemical_list: D000728:Androgens; D013250:Steroid Hydroxylases