Adaptive evolution in the SRZ chemoreceptor families of Caenorhabditis elegans and Caenorhabditis briggsae.

ABSTRACT: We investigated the possibility of positive selection acting on members of the putative seven-pass chemoreceptor superfamily in Caenorhabditis elegans, which comprises approximately 1,300 genes encoding seven-pass G protein-coupled receptors (GPCRs). Using a maximum-likelihood approach, we conducted statistical tests for evidence of codon sites where the ratio of nonsynonymous substitutions per nonsynonymous site to synonymous substitutions per synonymous site (d(N)/d(S)) was >1. Evidence for positive selection was found only for the srz family, about which virtually nothing specific is known. We extended the annotation of the srz gene family, establishing gene models for 60 srz genes in C. elegans and 28 srz genes in Caenorhabditis briggsae. d(N)/d(S) ratios varied dramatically in differe

SUBMITTER: Thomas JH 

PROVIDER: S-EPMC555475 | biostudies-literature | 2005 Mar

REPOSITORIES: biostudies-literature