Evaluation of sequence variation and selection in the bindin locus of the red sea urchin, Strongylocentrotus franciscanus.

TitleEvaluation of sequence variation and selection in the bindin locus of the red sea urchin, Strongylocentrotus franciscanus.
Publication TypeJournal Article
Year of Publication2000
AuthorsDebenham P, Brzezinski MA, Foltz KR
JournalJ Mol Evol
Volume51
Issue5
Pagination481-90
Date Published2000 Nov
ISSN0022-2844
KeywordsAlleles, Animals, Base Sequence, DNA, Evolution, Molecular, Genetic Variation, Glycoproteins, Molecular Sequence Data, Point Mutation, Polymorphism, Genetic, Receptors, Cell Surface, Sea Urchins, Selection, Genetic, Sequence Alignment, Sequence Analysis, DNA, Sequence Homology, Nucleic Acid
Abstract

Recent evidence suggests that gamete recognition proteins may be subjected to directed evolutionary pressure that enhances sequence variability. We evaluated whether diversity enhancing selection is operating on a marine invertebrate fertilization protein by examining the intraspecific DNA sequence variation of a 273-base pair region located at the 5' end of the sperm bindin locus in 134 adult red sea urchins (Strongylocentrotus franciscanus). Bindin is a sperm recognition protein that mediates species-specific gamete interactions in sea urchins. The region of the bindin locus examined was found to be polymorphic with 14 alleles. Mean pairwise comparison of the 14 alleles indicates moderate sequence diversity (p-distance = 1.06). No evidence of diversity enhancing selection was found. It was not possible to reject the null hypothesis that the sequence variation observed in S. franciscanus bindin is a result of neutral evolution. Statistical evaluation of expected proportions of replacement and silent nucleotide substitutions, observed versus expected proportions of radical replacement substitutions, and conformance to the McDonald and Kreitman test of neutral evolution all indicate that random mutation followed by genetic drift created the polymorphisms observed in bindin. Observed frequencies were also highly similar to results expected for a neutrally evolving locus, suggesting that the polymorphism observed in the 5' region of S. franciscanus bindin is a result of neutral evolution.

Alternate JournalJ. Mol. Evol.
PubMed ID11080371