Chemoreception is mediated in Caenorhabditis elegans by members of the seven-transmembrane G-protein-coupled receptor class (7TM GPCRs) of proteins which are of the serpentine type [1]. Srw is a solo family amongst the superfamilies of chemoreceptors. Chemoperception is one of the central senses of soil nematodes like C. elegans which are otherwise 'blind' and 'deaf' [2]. The genes encoding Srw do not appear to be under as strong an adaptive evolutionary pressure as those of Srz [3].

1: Divergent seven transmembrane receptors are candidate chemosensory receptors in C. elegans. Troemel ER, Chou JH, Dwyer ND, Colbert HA, Bargmann CI; Cell 1995;83:207-218. PMID:7585938

2: The putative chemoreceptor families of C. elegans. Robertson HM, Thomas JH; WormBook. 2006; [Epub ahead of print] PMID:18050473

3: Adaptive evolution in the SRZ chemoreceptor families of Caenorhabditis elegans and Caenorhabditis briggsae. Thomas JH, Kelley JL, Robertson HM, Ly K, Swanson WJ; Proc Natl Acad Sci U S A. 2005;102:4476-4481. PMID:15761060