HAP2(GCS1) is a deeply conserved sperm protein that is essential for gamete fusion. Here we use complementation assays to define major functional regions of the Arabidopsis thaliana ortholog using HAP2(GCS1) variants with modifications to regions amino(N) and carboxy(C) to its single transmembrane domain. These quantitative in vivo complementation studies show that the N-terminal region tolerat...

REVIEW Although fertilization has been studied for more than a century, the cell surface proteins mediating the process are only now becoming known. Gamete interaction in animals appears to be molecularly complex. Although it is difficult to generalize at present, diversity of structure may be a recurring theme in the evolution of fertilization proteins. Examples of rapid evolution of fertiliza...

BACKGROUND This investigation describes features of patients undergoing in vitro fertilisation (IVF) and embryo transfer (ET) where both gametes were obtained from anonymous donors. METHODS Gamete unsuitability or loss was confirmed in both members of seven otherwise healthy couples presenting for reproductive endocrinology consultation over a 12-month interval in Ireland. IVF was undertaken ...

The recent in vitro derivation of gamete-like cells from mouse embryonic stem (mES) cells is a major breakthrough and lays down several challenges, both for the further scientific investigation and for the bioethical and biolegal discourse. We refer here to these cells as gamete-like (sperm-like or oocyte-like, respectively), because at present there is still no evidence that these cells behave...

Gamete compatibility is fundamental to sexual reproduction. Wolbachia are maternally inherited endosymbiotic bacteria that manipulate gamete compatibility in many arthropod species. In Drosophila, the fertilization of uninfected eggs by sperm from Wolbachia-infected males often results in early developmental arrest. This gamete incompatibility is called cytoplasmic incompatibility (CI). CI is h...

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...

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...