The zinc finger transcription factor Gata4, is associated with gonadal development in many species. The present study characterizes temporal and spatial localization of Gata4 throughout gonadogenesis in porcine embryos. Immunohistochemical studies illustrated that Gata4 protein is present in the coelomic epithelium prior to histological differentiation of the nascent bipotential gonad, marking ...

Social insects are well known for their high level of cooperation. Workers of the primitively eusocial bumblebee Bombus terrestris are able to produce male offspring in the presence of a queen. Nonetheless, they only compete for reproduction, in the so-called competition phase, when the workforce is large enough to support the rearing of reproductives. So far, little is known about the proximat...

In many primitively eusocial wasp species new nests are founded either by a single female or by a small group of females. In the single foundress nests, the lone female develops her ovaries, lays eggs as well as tends her brood. In multiple foundress nests social interactions, especially dominance-subordinate interactions, result in only one 'dominant' female developing her ovaries and laying e...

Morphometric studies performed in several species of Neotropical social wasps from the tribe Epiponini showed that in some species there are marked differences between castes, while other species present highly distinct castes with differences only in ovarian development. This work analyzed females from six colonies of the social wasp Leipomeles dorsata (Fabricius) in which queens (egglayers) a...

A variety of mechanisms are engaged in sex determination in vertebrates. The teleost fish swamp eel undergoes sex reversal naturally and is an ideal model for vertebrate sexual development. However, the importance of proteome-wide scanning for gonad reversal was not previously determined. We report a 2-D electrophoresis analysis of three gonad types of proteomes during sex reversal. MS/MS analy...

Growth and testicular development between 7 and 15 mo of age were evaluated in bulls produced by mating sires of six breeds (Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli) to Angus, Hereford, and MARC III (four-breed composite) cows. At 12 mo of age, Angus- and Hereford-sired bulls had the heaviest body weight (P < 0.08 to 0.001), whereas Brahman- and Belgian Blue-sired bulls were int...

We compared the temporal dynamics of gametogenesis in diploid and triploid Pacific oysters (Crassostrea gigas) using histology. Oysters were reared in an estuarine farming site in Brittany over 3 years and their gametogenesis was monitored over the exceptionally hot summer of 2003. Both diploids and triploids showed active gametogenesis, but a high proportion of triploids remained at early stag...

Reproductive characteristics of Mossul bleak, Alburnus mossulensis, a native species of Cyprinidae family in Bibi-Sayyedan River of Semirom, Isfahan, were investigated by monthly sampling during December 2010 to December 2011. Five hundred and fourty three specimens (256 females, 159 males and 31 immature) were caught by a sein net (5 mm mesh size). The collected sampeles were anesthesized in 1...

Vestimentiferan tubeworms are significant members of deep-sea chemosynthetically-driven communities, including hydrothermal vents and cold seeps. The reproductive condition in this taxon is rarely studied because of sampling constraints inherent to these environments, and the lack of a simple methodology to quantify gonad development in vestimentiferans. We demonstrate that the amount of gonad ...

WNT signalling plays a central role in mammalian sex determination by promoting ovarian development and repressing aspects of testis development in the early gonad. Dickkopf homolog 1 (DKK1) is a WNT signalling antagonist that plays critical roles in multiple developmental systems by modulating WNT activity. Here, we examined the role of DKK1 in mouse sex determination and early gonadal develop...