BACKGROUND Reproductive isolation is a defining characteristic of populations that represent unique biological species, yet we know very little about the gene expression basis for reproductive isolation. The advent of powerful molecular biology tools provides the ability to identify genes involved in reproductive isolation and focuses attention on the molecular mechanisms that separate biologic...

The common vole is one ofthe most numerous rodents in Europe and Asia but its reproductive biology is not fully described. It is thought that females reach reproductive abilities at a very young age, however, there is no data concerning male sexual maturation. The aim of the present study was to determine the rate of sexual maturation of males of the common vole. Research was carried out on 4, ...

One crucial result of egg activation is the establishment of blocks on the zona pellucida and the egg plasma membrane to prevent fertilization by additional sperm. The mechanism(s) by which a mammalian egg regulates the establishment of the membrane block to polyspermy is largely unknown. Since Ca(2+) signaling regulates several egg activation events, this study investigates how sperm-induced C...

Male infertility is a fast-evolving area. Recently published evidence has challenged several established concepts and added to the knowledge in the field. Traditionally, the clinical assessment of the subfertile male includes a history and physical examination, hormonal evaluation and semen analyses. Regarding the latter, the World Health Organization has established new reference values that i...

is a landlocked population restricted to a 270 km stretch of the Kootenai River, which flows from western Montana through northern Idaho and into British Columbia. This population has shown an almost complete lack of natural juvenile recruitment since 1974. The total adult population in 1998 was estimated to be about 650 individuals and this fish is currently classified as endangered by the Ida...

Sperm motility is one of the three fundamental tenets of semen analysis providing diagnostic and prognostic information for both natural and assisted reproduction technology (ART) conception. The landmark papers of John MacLeod and Ruth Gold demonstrated clear differences between subfertile and fertile men in sperm motility (MacLeod and Gold, 1951) which have been confirmed by a plethora of sub...

The oviduct occupies a unique position in mammalian reproduction as the site of sperm transport, the final maturation of sperm and egg, fertilization, and the initial development of the embryo. This dissertation examines the factors that control the number, distribution and physiological state of spermatozoa in the oviduct. The golden hamster (Mesocricetus auratus) was used as the animal model....

Several species are characterised by male mating polymorphisms, which often associated with sperm competition for some phenotypes show specialisation. With high-resolution behavioural data, we used network analysis to quantify intensity; the probability of overlap ejaculates different males among competing European bitterling (Rhodeus amarus) in a large experimental mesocosm. Implementing Bayes...

"Capaci ta t ion" is a physiological event which alters sperm to permit rapid penetration through oocyte investments and fusion between gametes. Acrosomal "reaction," the physiological release of acrosomal contents, occurs after this facilitating process. In this study, acrosomal "disruption" of guinea pig and rat sperm was achieved in vitro by incubating sperm together with the follicular cont...