Two large families of chemoreceptor genes in the nematodes Caenorhabditis elegans and Caenorhabditis briggsae reveal extensive gene duplication, diversification, movement, and intron loss.

摘要: The str family of genes encoding seven-transmembrane G-protein-coupled or serpentine receptors related to the ODR-10 diacetyl chemoreceptor is very large, with at least 197 members in Caenorhabditis elegans genome. closely stl has 43 genes, and both families are distantly srd 55 genes. Analysis structures these indicates that a third them clearly likely pseudogenes. Preliminary surveys other candidate as many 800 pseudogenes 6% genome might encode 550 functional chemoreceptors constituting 4% C. protein complement. Phylogenetic analyses families, comparisons few orthologs briggsae, reveal ongoing processes gene duplication, diversification, movement. reconstructed ancestral for two have eight introns each, four which homologous. Mapping intron distributions on phylogenetic tree reveals each been lost times independently. Most were individually, best be explained by precise in-frame deletions involving nonhomologous recombination between short direct repeats their termini. [Alignment putatively proteins available from Pfam (http://genome. wustl.edu/Pfam); alignments all translations http://cshl.org/gr; author hughrobe@uiuc.edu]