Sexual reproduction occurs in many small eukaryotes by fusion of similar gametes (isogamy). In the absence of distinguishable sperm and eggs, male and female mating types are missing. However, species with distinct males and females have so prospered that almost all familiar plants and animals have these mating types. Why has sexual reproduction involving sperm and eggs been so successful? An a...

Sperm-zona adhesion is an essential event in mammalian fertilization, failure of which causes sterility. However, the molecular mechanisms involved in this process are still poorly understood. It has been suggested by few laboratories studying gamete interaction that acrosomal molecules are implicated in sperm-zona pellucida adhesion prior to the acrosome reaction (AR). Zonadhesin, a sperm-spec...

CD9 tetraspanin is the only egg membrane protein known to be essential for fertilization. To investigate its role, we have measured, on a unique acrosome reacted sperm brought in contact with an egg, the adhesion probability and strength with a sensitivity of a single molecule attachment. Probing the binding events at different locations of wild-type egg we described different modes of interact...

Wild animals usually die unexpectedly. After post-mortem, there is a short time for gamete rescue because tissue degeneration occurs rapidly in the field area. It is crucial to develop rescue strategies to obtain good gamete quality for future offspring production. Applications of reproductive biotechnologies, e.g. gamete cryopreservation, in vitro fertilization (IVF), intracytoplasmic sperm in...

Fisher (1947) and Bailey (1961) considered a two-locus tetrasomic model and exploited the basic features of genetic segregation and linkage of tetrasomic inheritance. They attempted to establish the relationship between the model parameters (the coefficients of double reduction at two linked loci, say α and β respectively, and recombination frequency between them, r) and frequencies of gamete m...

Macrocysts in Dictyostelium discoideum possess prototypic features of sexual reproduction and are useful for understanding the basic mechanisms of the reproductive process. Here, we randomly analyzed 1,071 gamete cDNAs, and then constructed a gamete-specific subtraction library, FC-IC. Nucleotide sequences of all 903 FC-IC clones were determined and clustered into 272 independent genes. Express...

Many studies on selective fertilization in maize, Zea mays L., have been reported since it was detected that genetic factor (s) linked to the de gene is responsible for distortion of segregation in F 2.2> On the other hand, some applications of the selective fertilization to maize breeding, i.e. prediction for combining abi lity of inbred lines or F1 seed production without using cytoplasmic ma...

The rapidly increasing global population has bowed the attention of family planning and associated reproductive health programmes in the direction of providing a safe and reliable method which can be used to limit family size. The world population is estimated to exceed a phenomenal 10 billion by the year 2050 A.D., thus presenting a real jeopardy of overpopulation with severe implications for ...

In recent years, concerns have been raised regarding the potentially negative consequences of gamete donation for parent-child relationships. Findings are presented of a study of families with an infant conceived by gamete donation. Fifty donor insemination families and 51 egg donation families were compared with 80 natural conception families on standardized interview and questionnaire measure...

Gamete fusion is the fundamental first step initiating development of a new organism. Female mice with a gene knockout for the tetraspanin CD9 (CD9 KO mice) produce mature eggs that cannot fuse with sperm. However, nothing is known about how egg surface CD9 functions in the membrane fusion process. We found that constructs including CD9's large extracellular loop significantly inhibited gamete ...