by Methuen .
Written in English
|The Physical Object|
|Number of Pages||138|
A sex-determination system is a biological system that determines the development of sexual characteristics in an organisms that create their offspring using sexual reproduction have two sexes. Occasionally, there are hermaphrodites in place of one or both sexes. There are also some species that are only one sex due to parthenogenesis, the act of a female reproducing without. 1st Edition Published on Septem by CRC Press This book is the first to report that research in allogenics/xenogenics has conclusively shown that fis Sex Determination in Fish - 1st Edition - T. J. Pandian - Routledge B. Book Description. The cloning of the SRY gene and the attainment of XX mice transgenic for the Sry gene opened a new era in research on sex determination. This book surveys current knowledge of sex chromosomes and sex determination in all vertebrate classes, relying on the restriction of genetic recombination in sex chromosomes as the unifying. Sex Determination, Volume , the latest release in the Current Topics in Developmental Biology series, contains current reviews in the field of vertebrate sex covers molecular pathways of sex determination in genetic and environmental species and encompasses both sex determination of somatic lineages and commitment of germ cells to male or female fate.
In some species, such as Bonellia and Crepidula, sex determination is brought about by the position of the individual with regard to other individuals of the same species. By agreement with the publisher, this book is accessible by the search feature, but cannot be : Scott F Gilbert. Sex determination in animals is an integral part of reproduction. In general, sex determination describes the genetic and environmental processes that influence sex differentiation, whereas sex differentiation is the physical realization of these events in terms of testicular or ovarian development (Mittwoch, ). In other words, sex. Mechanisms of sex determination Chromosomal sex determination: In flies and mammals females are the homogametic sex (XX) and males the heterogametic sex (XY). In butterflies and birds males are the homogametic sex (ZZ) and females the heterogametic sex (ZW). Drosophila melanogaster (fruit fly) XX females; XY males X:autosome ratio determines sex. Sex Determination •Sexual reproduction is the results of meiosis and fertilization •Sexual phenotypes (the sexes) –male and female –Differ in gamete size •Sex determination –mechanism by which sex is established •Monoecious –organisms with both male and female reproductive structures (hermphroditism).
A sex-determination is the biological system that determines the development of sexual characteristics in an organism. There are two different types of sexes – male and female. Chromosome plays an essential role in determining the sex of an individual. However, in the field of sex determination there was also an unexpected discovery: temperature-dependent sex determination in reptiles. That vertebrates as highly evolved as reptiles could develop into males or females without sex chromosomes and perhaps sex-determining genes was a surprise to many scientists, and indicated that there was. Environmental sex determination: sex is triggered by environmental cues, such as temperature, pH, social interactions, and seasonality (e.g., many reptiles and some fish). Genotypic sex determination: an individual's sex is established by its genotype (e.g., mammals, birds, amphibians, most insects, some reptiles and fish, and some plants). Introduction. Diverse mechanisms are involved in the determination of sex in lower animals, such as the ratio of the number of X chromosomes to autosomes in Drosophila (Hodgkin, ) or the ambient temperature during incubation of the embryo in turtles, alligators, crocodiles and some lizards (Charnier, ; Bull, , , ; Head, May & Pendleton, ; Deeming & Ferguson, ; Ewert.