DNA polymorphism and selection at the bindin locus in three Strongylocentrotus sp. (Echinoidea). Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Balakirev, Evgeniy; Anisimova, Maria; Pavlyuchkov, Vladimir; Ayala, Francisco
• Is Part Of: BMC genetics. Volume 17:Issue 1(2016)
• Page Start: 1
• Page End: 16
• Publication Date: 2016-12
• Subjects: Genetics -- Periodicals; 576.505
• DOI: 10.1186/s12863-016-0374-5
• Languages: English
• ISSNs: 1471-2156

Abstract

Abstract Background The sperm genebindin encodes a gamete recognition protein, which plays an important role in conspecific fertilization and reproductive isolation of sea urchins. Molecular evolution of the gene has been extensively investigated with the attention focused on the protein coding regions. Intron evolution has been investigated to a much lesser extent. We have studied nucleotide variability in the completebindin locus, including two exons and one intron, in the sea urchinStrongylocentrotus intermedius represented by two morphological forms. We have also analyzed all availablebindin sequences for two other sea urchin species, S. pallidus andS. droebachiensis . Results The results show that thebindin sequences from the two forms ofS. intermedius are intermingled with no evidence of genetic divergence; however, the forms exhibit slightly different patterns inbindin variability. The level of thebindin nucleotide diversity is close forS. intermedius andS. droebachiensis, but noticeably higher forS. pallidus . The distribution of variability is non-uniform along the gene; however there are striking similarities among the species, indicating similar evolutionary trends in this gene engaged in reproductive function. The patterns of nucleotide variability and divergence are radically different in thebindin coding and intron regions. Positive selection is detected in thebindin coding region. The neutrality tests as well as the maximum likelihood approaches suggest the action of diversifying selection in thebindin intron. Conclusions Significant deviation from neutrality has been detected in thebindin coding region and suggested in the intron, indicating the possible functional importance of thebindin intron variability. To clarify the question concerning possible involvement of diversifying selection in thebindin intron evolution more data combining population genetic and functional approaches are necessary.