Sex determination is a critical component of forensic identification, the standard genetic method for which is detection of the single copy amelogenin gene that has differing homologues on the X and Y chromosomes. However, this assay may not be sensitive enough when DNA samples are minute or highly compromised, thus other strategies for sex determination are needed. In the current research, two...

In order to have a good perspective of wild animals, it is necessary to determine their population and genetic structure. It provides an opportunity to decide on better conservation managements. In the wilderness, due to the escapable nature and sometimes not having the distinguishable bisexual appearance, sex identification could be difficult by observing animals. The X- and Y- chromosome link...

Some fishes mature and function as one sex and later transform to the other sex in response to social interactions. Previous evidence suggested that a change in developmental timing may be involved in the evolution of adult sex change in fishes. The most recent support for this idea came from reports that sex in the Midas cichlid, Amphilophus citrinellus, was determined by social conditions exp...

either evenly-balanced sex ratios or sex ratios in favour of females, as in states like Kerala and Manipur. In the Northwest sex ratios have been far more imbalanced against females among specific land-owning communities (such as Rajputs, Jats, Gujjars) and relatively more balanced among almost all have shifted to a deficit of females and are slowly moving towards the all-India pattern. Lower s...

We describe here the current status and future prospects of sex-determination studies in the silkworm, Bombyx mori. The sex of Bombyx is strongly controlled by the presence of the W chromosome. Although several classical studies suggested that a presumptive feminizing gene (Fem) is located at a limited portion of the W chromosome, the Fem gene has not yet been cloned. Recently, the homologues o...

Sex determination in flies relies on the different ratio of X chromosomes to autosomes in XX females and XY males. Mammals have a male-determining Y-linked gene, but may retain dosage-related elements.

Throughout the major part of history, theories of sex determination had to be formulated in the absence of knowledge of ova and spermatozoa. The most persistent theory postulated that males are associated with the right parental side and females with the left side. At the end of the 19th century, sex was thought to be determined by nutrition. Recent findings regarding bilateral asymmetry in hum...

Frog sex chromosomes offer an ideal system for advancing our understanding of genome evolution and function because of the variety of sex determination systems in the group, the diversity of sex chromosome maturation states, the ease of experimental manipulation during early development. After briefly reviewing sex chromosome biology generally, we focus on what is known about frog sex determina...

Sex determination was a founding topic of C. elegans research. After three decades of research, a complex signal transduction pathway with multiple layers of regulation has been elucidated. This pathway links karyotype to phenotype by coordinating the development of sexually dimorphic tissues. In this article, this pathway is placed in two broader contexts. The first is that of nematodes and an...

Sex allocation theory predicts that mothers should adjust their sex-specific reproductive investment in relation to the predicted fitness returns from sons versus daughters. Sex allocation theory has proved to be successful in some invertebrate taxa but data on vertebrates often fail to show the predicted shift in sex ratio or sex-specific resource investment. This is likely to be partly explai...