Expression of Dmrt1 in a turtle with temperature-dependent sex determination

Abstract

There is a variety of sex determining mechanisms among vertebrates. Many reptiles possess temperature-dependent sex determination (TSD), in which the incubation temperature of the egg determines the sex of the hatchling. The red-eared slider turtle, Trachemys scripta has often been used as a model system for examining the physiology of TSD. In the current study, the expression of Dmrt1 was examined during TSD in this turtle. Dmrt1 is a putative regulator of sex determination/differentiation and has been identified in a variety of vertebrates, including fishes, amphibians, reptiles, birds, and mammals. Specifically, Dmrt1 has been shown to be up-regulated in a male-specific pattern during embryonic development in many vertebrates. In the current study, the expression patterns of Dmrt1 were examined in the developing adrenal-kidney-gonad complexes of T. scripta during embryonic development. Using a quantitative competitive RT-PCR, Dmrt1 was shown to be up-regulated during the thermosensitive period of sex determination in males. In contrast, levels of Dmrt1 remained low in females throughout the thermosensitive period. These data suggest that the up-regulation of Dmrt1 may play a role in male sex determination/sex differentiation during TSD in T. scripta.

Up-regulation of P450arom and down-regulation of Dmrt-1 genes in the temperature-dependent sex reversal from genetic males to phenotypic females in a salamander

“…Up-regulation of Dmrt1 was observed in sex-reversed XX-neomales in a frog (Shibata et al 2002) and in developing male gonad of a turtle incubated at the male-producing temperature (Murdock and Wibbels, 2003b).…”

Expression of Sox9, Mis, and Dmrt1 in the gonad of a species with temperature‐dependent sex determination

“…In the American alligator, gonadal expression of Dmrt1 before and during the TSP is also greater in males, but increases through development in both sexes, raising questions about its function (Smith et al, 1999a). In T. scripta, dimorphic expression during the TSP has been reported, beginning at either stage 15 (Kettlewell et al, 2000) or stage 17 (Murdock and Wibbels, 2003).…”

Molecular Cloning of Full-Length Dmrt1 cDNA of Reeves Turtle (Chinemys reevesii)

“…In alligators (Alligator mississippiensis), dmrt1 expression was initially detected using RT-PCR in the urogenital systems of embryos incubated at both male-and female-producing temperatures; however, gonadal expression subsequently became higher in developing male embryos than in female embryos [23]. In Trachemys scripta, up-regulation of dmrt1 was observed in the developing male gonads of a turtle incubated at male-reproducing temperature [16]. Chinemys reevesii is the turtle commonly seen in lakes, rivers, and ponds in Japan, China, Korea, and Taiwan.…”