The advantage of sex has been among the most debated issues in biology. Surprisingly, the question of why sexual reproduction generally requires the combination of distinct gamete classes, such as small and large gametes, or gametes with different mating types, has been much less investigated. Why do systems with alternative gamete classes (i.e. systems with either anisogamy or mating types or ...

In angiosperms, a zygote generally divides into a two-celled proembryo consisting of an apical and a basal cell that possess different cell fates. This first division of the zygote is a putative step in the formation of the apical-basal axis of the proembryo. The gamete fusion activates the egg, and the gamete fusion site on the zygote has been reported to provide a possible cue for subsequent ...

Fertilization comprises a series of precisely orchestrated steps that culminate in the fusion of male and female gametes. The most intimate steps during fertilization encompass gamete recognition, adhesion and fusion. In animals, some binding-effector proteins and enzymes have been identified that act on the cell surfaces of the gametes to regulate gamete compatibility and fertilization success...

Double fertilization in angiosperms involves several successive steps, including guidance and reception of the pollen tube and male-female gamete recognition. Each step entails extensive communication and interaction between two different reproductive cell or tissue types. Extensive research has focused on the pollen tube, namely, its interaction with the stigma and reception by maternal cells....

dear editor, today some infertile couples who want to have children have request for getting gametes which is a confidential process. according to law, no person must know the identity of the gamete providers (1). confidentiality of information relating to gamete and embryo donation can cause serious ethical problems. in some countries, forming the bank of gametes and embryos is intended as a w...

Fertilization is one of the most important processes in all organisms utilizing sexual reproduction. In a previous study, we succeeded in identifying a novel male gametic transmembrane protein GCS1 (GENERATIVE CELL SPECIFIC 1), also called HAP2 (HAPLESS 2) in the male-sterile Arabidopsis thaliana mutants, as a factor critical to gamete fusion in flowering plants. Interestingly, GCS1 is highly c...

Wars and natural disasters causing thousands of deaths and forcing millions to fl ee occur frequently and are widely reported to a global audience. However, responses in terms of charity donations, demonstrations, political response and military intervention are dramatically different between one case and the next. When and why do we care about victims of humanitarian crises? Michael Gross inve...

The practice of gamete donation has, until recently, been shrouded in secrecy. The stigma associated with infertility and, in particular, donor insemination has been the main factor contributing to this secrecy. Over the last 20 years, this secrecy and the anonymity of the gamete donors has been challenged. In the first instance, the challenge came from governments in some countries legislating...

The fusion of Chlamydomonas gamete membranes leads to rapid degradation of FUS1 and HAP2, proteins required for gamete fusion. This provides a mechanism to prevent any subsequent fusion events, thereby preventing polygamy.

We have studied the antibodies to sexual stage antigens of Plasmodium falciparum in human sera from Papua New Guinea where intense transmission of P. falciparum occurs as well as the less prevalent P. malariae and P. vivax. In extracts of gametes of P. falciparum we have studied the reactivity of serum antibodies with antigens labeled with 125I on the surface of the gametes as well as intracell...