title: Selection in the rapid evolution of gamete recognition proteins in marine invertebrates.
abstract: Animal fertilization is governed by the interaction (binding) of proteins on the surfaces of sperm and egg. In many examples presented herein, fertilization proteins evolve rapidly and show the signature of positive selection (adaptive evolution). This review describes the molecular evolution of fertilization proteins in sea urchins, abalone, and oysters, animals with external fertilization that broadcast their gametes into seawater. Theories regarding the selective forces responsible for the rapid evolution driven by positive selection seen in many fertilization proteins are discussed. This strong selection acting on divergence of interacting fertilization proteins might lead to prezygotic reproductive isolation and be a significant factor in the speciation process. Since only a fraction of all eggs are fertilized and only an infinitesimal fraction of male gametes succeed in fertilizing an egg, gametes are obviously a category of entities subjected to intense selection. It is curious that this is never mentioned in the literature dealing with selection, perhaps because we know so little about fitness differences among gametes. (Ernst Mayr, 1997).
authors: Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0202, USA. vvacquier@ucsd.edu
authors: Victor D
authors: VD
authors: Vacquier
authors: Willie J
authors: WJ
authors: Swanson
mesh_terms: D000818:Animals; D004527:Egg Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D019143:Evolution, Molecular; D005260:Female; D005306:Fertilization / Q000235:genetics / Q000502:physiology*; D049851:Gastropoda / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D008297:Male; D009088:Mucoproteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D010125:Ostreidae / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012617:Sea Urchins / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D012641:Selection, Genetic; D013045:Species Specificity; D013084:Sperm-Ovum Interactions / Q000235:genetics
chemical_list: D004527:Egg Proteins; D009088:Mucoproteins; D011956:Receptors, Cell Surface; C113623:VERL protein, Haliotis; C099881:egg jelly ligand receptors, Strongylocentrotus purpuratus; C035027:egg surface sperm receptor; C010393:lysin, gastropoda