Nonsynonymous Substitution in Abalone Sperm Fertilization Genes Exceeds Substitution in Introns and Mitochondrial DNA

Strong positive Darwinian selection acts on two sperm fertilization proteins, lysin and 18-kDa protein, from abalone (Haliotis). To understand the phylogenetic context for this dramatic molecular evolution, we obtained sequences of mitochondrial cytochrome c oxidase subunit I (mtCOI), and genomic se...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1998-09, Vol.95 (18), p.10676-10681
Main Authors: Metz, Edward C., Robles-Sikisaka, Refugio, Vacquier, Victor D.
Format: Article
Language:English
Subjects:
Abalone
Animals
Base Sequence
Biological Sciences
Biological taxonomies
Calibration
Deoxyribonucleic acid
DNA
DNA Primers
DNA, Mitochondrial - genetics
Evolution
Evolution, Molecular
Exons
Fertilization - genetics
Genetic Variation
GTP-Binding Proteins - genetics
Haliotis
Introns
Male
Marine
Molecular Sequence Data
Mollusca - genetics
Mucoproteins - genetics
Mutation
Nucleotides
Phylogeny
Polymerase chain reaction
Proteins
Reproduction
Species Specificity
Spermatozoa
Spermatozoa - physiology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Strong positive Darwinian selection acts on two sperm fertilization proteins, lysin and 18-kDa protein, from abalone (Haliotis). To understand the phylogenetic context for this dramatic molecular evolution, we obtained sequences of mitochondrial cytochrome c oxidase subunit I (mtCOI), and genomic sequences of lysin, 18-kDa, and a G protein subunit. Based on mtDNA differentiation, four north Pacific abalone species diverged within the past 2 million years (Myr), and remaining north Pacific species diverged over a period of 4-20 Myr. Between-species nonsynonymous differences in lysin and 18-kDa exons exceed nucleotide differences in introns by 3.5- to 24-fold. Remarkably, in some comparisons nonsynonymous substitutions in lysin and 18-kDa genes exceed synonymous substitutions in mtCOI. Lysin and 18-kDa intron/exon segments were sequenced from multiple red abalone individuals collected over a 1,200-km range. Only two nucleotide changes and two sites of slippage variation were detected in a total of >29,000 nucleotides surveyed. However, polymorphism in mtCOI and a G protein intron was found in this species. This finding suggests that positive selection swept one lysin allele and one 18-kDa allele to fixation. Similarities between mtCOI and lysin gene trees indicate that rapid adaptive evolution of lysin has occurred consistently through the history of the group. Comparisons with mtCOI molecular clock calibrations suggest that nonsynonymous substitutions accumulate 2-50 times faster in lysin and 18-kDa genes than in rapidly evolving mammalian genes.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.95.18.10676