نتایج جستجو برای: sex differentiation
تعداد نتایج: 426769 فیلتر نتایج به سال:
Over the past decade, knowledge of the genetic control of human sex differentiation has greatly expanded our understanding of the developmental processes needed to form a male or female. The purpose of this review is to discuss how transcription factors are relevant to such processes. Additionally, an attempt is made to relate current knowledge of these factors with gender development of subjec...
The zygotic function of the hermaphrodite (her) gene of Drosophila plays an important role in sexual differentiation. Our molecular genetic characterization of her suggests that her is expressed sex non-specifically and independently of other known sex determination genes and that it acts together with the last genes in the sex determination hierarchy, doublesex and intersex, to control female ...
Most of the work on sex differentiation is devoted to studies on amniotes with particular emphasis on mammals. Our present picture of sex differentiation is formed by the contributions of geneticists, embryologists and endocrinologists. For decades there has been a controversy as to whether sex steroids or (hypothetical) inductor substances play a major role in the process of sex differentiatio...
Mammalian sex determination involves complex interacting networks of cellular and hormonal signals leading to the development of male or female phenotypes. Three main sequential processes are involved: first, the establishment of chromosomal sex at fecundation (genetic sex); second, the development of the undifferentiated gonad into either testes or ovaries (gonadal sex); and third, differentia...
The phenotypic sex of many teleost fishes including flounders can be experimentally altered by treating embryos or larvae with varied temperatures or sex-steroid hormones. To analyse the sex determination mechanism, especially the role of cytochrome P450 aromatase (P450arom), an enzyme that catalyses the conversion of androgens to estrogens, in temperature-dependent gonadal sex differentiation ...
Sex determination in mammals has been defined as those events that fix the nature of the germ cell and the gonad, while other processes influencing sexual form and function such as hormone action constitute sex differentiation (Austin et al., 1981). Such determination involves the separation of germline and soma, controlled initially by maternal genes and then by the zygotic genome after fertil...
We found that sexual differentiation of all the nymphal stages of Pycnoscelus indicus (Fabricius) was possible by observing the developmental features of their posterior abdominal segments. Using this observation, the sex of even the 1st stage instar nymph could be determined. The female of the 1st to 6th stage instar nymph possess a V-shaped notch at the middle of the posterior edge of the 9th...
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