A duplicated copy of DMRT1 in the sex-determining region of the Y chromosome of the medaka, Oryzias latipes

Abstract

The genes that determine the development of the male or female sex are known in Caenorhabditis elegans, Drosophila, and most mammals. In many other organisms the existence of sex-determining factors has been shown by genetic evidence but the genes are unknown. We have found that in the fish medaka the Y chromosome-specific region spans only about 280 kb. It contains a duplicated copy of the autosomal DMRT1 gene, named DMRT1Y. This is the only functional gene in this chromosome segment and maps precisely to the male sex-determining locus. The gene is expressed during male embryonic and larval development and in the Sertoli cells of the adult testes. These features make DMRT1Y a candidate for the medaka male sex-determining gene.

Evolutionary history of two divergent Dmrt1 genes reveals two rounds of polyploidy origins in gibel carp

“…Several sex determination and sex chromosome-linked genes in vertebrates such as Dmy in medaka (Matsuda et al, 2002;Nanda et al, 2002), DM-W in the W chromosome of African clawed frog (Yoshimoto et al, 2008), and Dmrt1 in the Z chromosome of birds (Smith et al, 2009), have been shown to be recently duplicated homologs of Dmrt1. Because of the high evolutionary conservation and the newly recruited role in vertebrates (Herpin and Schartl, 2011;Xia et al, 2007), Dmrt1 also allows us to analyze the evolutionary history of genome duplication through examination of divergence and phylogeny of the duplicated genes.…”

Differential and spermatogenic cell-specific expression of DMRT1 during sex reversal in protogynous hermaphroditic groupers

“…In birds, the Z chromosome-linked DMRT1 is the best candidate for a male master testis-determining gene (Nanda et al, 1999). Furthermore, the Y-linked sex determina-tion gene DMY in the teleost Japanese medaka has been shown to be a duplicate of autosomal gene DMRT1 and a relatively recent product in a short period of evolutionary time (Matsuda et al, 2002;Nanda et al, 2002;Zhang, 2004). So DMRT1 is not only conservative but also changeable to fulfill novel functions.…”

Germline stem cells are critical for sexual fate decision of germ cells

“…However, contrary to the initial prediction that Sry is conserved among vertebrates, many animals do not possess an Sry homolog. Ten years after the discovery of Sry , DMY / Dmrt1bY was identified as the sex determination gene on the sex chromosome in the teleost fish, medaka 5, 6. Since this discovery, other sex determination genes have also been identified in various vertebrates.…”

“…All sex determination genes examined thus far are expressed in the somatic (supporting) cells that directly surround the germ cells in the gonad 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. Therefore, it is reasonable to speculate that the sexual fate of germ cells (in other words, the fate decision of germ cells to develop eggs or sperms) is triggered by the sex of the surrounding somatic cells during a normal sex determination process.…”