title: The molecular evolution of sperm bindin in six species of sea urchins (Echinoida: Strongylocentrotidae).
abstract: The acrosomal protein bindin attaches sperm to eggs during sea urchin fertilization. Complementary to ongoing functional biochemical studies, I take a comparative approach to explore the molecular evolution of bindin in a group of closely related free-spawning echinoid species. Two alleles of the mature bindin gene were sequenced for each of six species in the sea urchin family Strongylocentrotidae. The nucleotide sequences diverged by at least 1% per Myr at both silent and replacement sites. Two short sections flanking the conserved block show an excess of nonsynonymous substitutions. Each is homologous to a region that had been identified as a target of selection in other sea urchin comparisons. A large proportion of the bindin-coding sequence consists of a highly variable repeat region. Bindin sequences, even including the large intron, could not resolve the branching order among five of the species.
authors.affiliation: Department of Ecology and Evolution, State University of New York at Stony Brook, USA. c.h.biermann@biosci.hull.ac.uk
authors.forename: C H
authors.initials: CH
authors.lastname: Biermann
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005260:Female; D014644:Genetic Variation; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D017354:Point Mutation; D011956:Receptors, Cell Surface; D012617:Sea Urchins / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013084:Sperm-Ovum Interactions / Q000235:genetics; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D011956:Receptors, Cell Surface; C035027:egg surface sperm receptor