RRC ID 2880
Author Takehana Y, Naruse K, Hamaguchi S, Sakaizumi M.
Title Evolution of ZZ/ZW and XX/XY sex-determination systems in the closely related medaka species, Oryzias hubbsi and O. dancena.
Journal Chromosoma
Abstract A DM-domain gene on the Y chromosome was identified as the sex-determining gene in the medaka, Oryzias latipes, and named DMY (also known as dmrt1bY). However, this gene is absent in most Oryzias fishes, suggesting that closely related species have another sex-determining gene. In fact, it has been demonstrated that the Y chromosome in O. dancena is not homologous to that in O. latipes, whereas both species have an XX/XY sex-determination system. Through a progeny test of sex-reversed fish and a linkage analysis of isolated sex-linked DNA markers, we show that O. hubbsi, which is one of the most closely related species to O. dancena, has a ZZ/ZW system. In addition, genetic and fluorescence in situ hybridization mapping of the sex-linked markers revealed that sex chromosomes in O. hubbsi and O. dancena are not homologous, indicating different origins of these ZW and XY sex chromosomes. Furthermore, we found that O. hubbsi has morphologically heteromorphic sex chromosomes, in which the W chromosome has 4,6-diamidino-2-phenylindole (DAPI)-positive heterochromatin blocks and is larger than the Z chromosome, although such differentiated sex chromosomes have not been observed in other Oryzias species. These findings suggest that a variety of sex-determining mechanisms and sex chromosomes have evolved in Oryzias.
Volume 116(5)
Pages 463-70
Published 2007-10-1
DOI 10.1007/s00412-007-0110-z
PMID 17882464
MeSH Animals Evolution, Molecular* In Situ Hybridization, Fluorescence Indoles / metabolism Oryzias / genetics* Sex Chromosomes / genetics* Sex Chromosomes / physiology Sex Determination Processes Y Chromosome / genetics*
IF 3.442
Times Cited 66
Medaka O. hubbsi (RS273) O. javanicus(Penang) (RS831) cDNA clone (OLb22.11h)