BACKGROUND Sex determination processes vary widely among different vertebrate taxa, but no group offers as much diversity for the study of the evolution of sex determination as teleost fish. However, the knowledge about sex determination gene cascades is scarce in this species-rich group and further difficulties arise when considering hybrid fish taxa, in which mechanisms exhibited by parental ...

BACKGROUND The relationship between the activity of the epiphysis and gonads in rats of different sex and age in different seasons of the year was determined by studying the levels of melatonin and testosterone in the blood plasma. Determination of the levels of melatonin and testosterone in the serum of rats was carried out by enzyme-linked immunosorbent assay. To assess the relationship betwe...

To clarify the sexually dimorphic mechanisms of gonadal sex differentiation, we established an in vitro culture system for gonadal sex differentiation using the teleost fish Oreochromis niloticus. In vivo, the entry of germ cells into meiosis occurs around 35 days after hatching (dah) in XX gonads, whereas in XY gonads, meiotic cells became differentiated around 85 dah. In our in vitro culture ...

In vertebrates, several genes which are differentially expressed in various species, have been implicated in sex determination and gonadal differentiation. We used immunolocalization to study the expression pattern of three proteins AMH, DMRT1, RSPO1 involved in the sexual differentiation of gonads. The pattern of AMH, DMRT1 and RSPO1 expression was analyzed in X. laevis and in five other diver...

Sex in birds is controlled genetically (ZZ male: ZW female), but the genetic mechanism remains unclear. While some evidence points to the involvement of Z sex chromosome dosage, other data favour a dominant female-determining gene carried on the W sex chromosome. An intriguing candidate gene located on the chicken W chromosome is HINTW, which encodes an aberrant form of a hydrolase enzyme. In c...

In many animals, primordial germ cells (PGCs) migrate into developing gonads. There, they proliferate and differentiate into female and male germ stem cells (GSCs), oogonia and spermatogonia, respectively. Few studies have focused on the molecular mechanisms underlying the development of GSC sex determination. Here, we investigated the expression of the transcription factor Dmrt1 and a phosphor...

Mammals possess an XX/XY chromosomal system for sex determination. The presence of SRY, a masterregulatory gene on the Y chromosome, is necessary to induce the undifferentiated, bipotential gonadal primordium (the embryonic genital ridge) to develop as a testis. In the absence of SRY, it develops as an ovary I. Once the gonads differentiate, their maleor female-specific endocrine function is re...

backgrounds:there are some evidences that cholesterol can affect fish reproductive system. objectives: in this study the effect of high diet cholesterol on fish sex hormones and gonads weight was investigated. methods: a randomized experiment was conducted on 90 immature common carp. the fishes were divided into three groups with three replicates each (control, 0.5% cholesterol diet, and 1% cho...

Sex determination in mammals and birds is chromosomal, while in many reptiles sex determination is temperature dependent. Morphological development of the gonads in these systems is conserved, suggesting that many of the genes involved in gonad development are also conserved. The genes SF1, WT1 and DAX1 play various roles in the mammalian testis-determining pathway. SF1 and WT1 are thought to i...