Gamete interaction: Is it species‐specific?

Abstract

Reproductive isolation is pivotal to maintain species separation and it can be achieved through a plethora of mechanisms. In addition, the development of barriers to gamete interaction may drive speciation. Such barriers to interspecific gamete interaction can be prezygotic or postzygotic. Considering the great diversity in animal species, it is easy to assume that regulation of the early steps of fertilization is critical to maintain species identity. One prezygotic mechanism that is often mentioned in the literature is that gamete interaction is limited to gametes of the same species. But do gametes of all animals interact in a species-specific way? Are gamete interactions completely species-specific or perhaps just species-restricted? In species in which species-restrictions have been described, is the interspecies barrier at one major step in the fertilization process or is it a combination of partially restricted steps that together lead to a block in interspecific fertilization? Are the mechanisms used to avoid interspecific crosses different between free-spawning organisms and those with internal fertilization? This review will address these questions, focusing on prezygotic barriers, and will describe what is known about the molecular biology that may account for species-limited gamete recognition and fertilization.

Maternal Control of Male-Gamete Delivery inArabidopsisInvolves a Putative GPI-Anchored Protein Encoded by theLORELEIGene

“…GAPs expressed on the surface of mammalian sperm cells are also important for fertilization because cleavage of these proteins by ACE and release into the extracellular medium are required for sperm cell capacitation in oocyte binding (Kondoh et al, 2005). In mammals, species specificity in fertilization occurs through the interactions between sperm cell and egg cell, with cell surface proteins acting as key determinants (reviewed in Wassarman, 1999;Vieira and Miller, 2006). In flowering plants, barriers are provided by the sporophytic tissues, such as the stigma and transmitting tract, and play a major role in preventing interspecies fertilization for distantly related species.…”

Speciation and the evolution of gamete recognition genes: pattern and process

“…Fertilization occurs after gamete attachment and fusion, which depends on the action of binding-effector proteins and enzymes that act at cell surfaces. These mechanisms can be species specific or quite general among taxa (Vieira and Miller, 2006). Because basic fertilization demands the interaction of proteins produced by male and female genomes, it can be driven by evolutionary pressures that act on mating systems such as gender conflict (Gavrilets and Waxman, 2002;Gavrilets and Hayashi, 2005;Tomaiuolo et al, 2007), reinforcement (Geyer and Palumbi, 2003) or other aspects of the evolution of reproductive isolation (Tomaiuolo et al, 2007).…”

Ca2+ signaling differentiation during oocyte maturation

“…It is intriguing that Ca 2þ is the evolutionarily conserved signal for egg activation, given that different species have evolved elaborate mechanisms to ensure reproductive isolation, such as the inability of interspecies gamete fusion, which is thought to be a driving force for speciation (Vieira and Miller, 2006). Ca 2þ is a fitting second messenger to mediate egg activation across phylogeny, because of its ability to induce diverse cellular responses (Bootman et al, 2002).…”