Histological and immunohistochemical analysis of gonadal development in the veiled chameleon (Chamaeleo calyptratus).

Chameleons are a family of lizards distinguished by several unique features related to their arboreal lifestyles, such as a ballistic tongue, skin color changes, independent movement of both eyes, a prehensile tail, and cleft hands and feet. The veiled chameleon (Chamaeleo calyptratus) has been proposed as a promising model species for studying squamate biology. Despite its potential, the developmental biology of this species remains poorly understood, particularly in terms of gonadal development.

Histological Analysis of Gonadal Ridge Development and Sex Differentiation of Gonads in Three Gecko Species.

Reptiles constitute a highly diverse group of vertebrates, with their evolutionary lineages having diverged relatively early. The types of sex determination exemplify the diversity of reptiles; however, there are limited data regarding the gonadal development in squamate reptiles. Geckos constitute a group that is increasingly used in research and that serves as a potential reptilian model organism.

Histological analysis of early gonadal development in three bird species reveals gonad asymmetry from the beginning of gonadal ridge formation and a similar course of sex differentiation.

The developing gonads constitute a valuable model for studying developmental mechanisms because the testes and ovaries, while originating from the same primordia, undergo two different patterns of development. So far, gonadal development among birds has been described in detail in chickens, but literature on the earliest stages of gonadogenesis is scarce. This study presents changes in the structure of the gonads in three species of breeding birds (chicken, duck, and pigeon), starting from the first signs of gonadal ridge formation, that is, the thickenings of the coelomic epithelium.

The Central Role of Cadherins in Gonad Development, Reproduction, and Fertility.

Cadherins are a group of membrane proteins responsible for cell adhesion. They are crucial for cell sorting and recognition during the morphogenesis, but they also play many other roles such as assuring tissue integrity and resistance to stretching, mechanotransduction, cell signaling, regulation of cell proliferation, apoptosis, survival, carcinogenesis, etc. Within the cadherin superfamily, E- and N-cadherin have been especially well studied.