title: TGF-beta and the evolution of nematode parasitism.
abstract: The many similarities between arrested dauer larvae of free-living nematodes and infective L3 of parasitic nematodes has led to suggestions that they are analogous lifecycle stages. The control of the formation of dauer larvae in Caenorhabditis elegans is well understood, with a TGF-beta-superfamily growth factor playing a central role. Recent analyses of the expression of homologous TGF-beta genes in parasitic nematodes has allowed this analogy to be tested; but the results so far do not support it. Rather, the results imply that in the evolution of animal parasitism, parasitic nematodes have taken signalling pathways and molecules from their free-living ancestors and used them in different ways in the evolution of their parasitic lifestyles.
authors.affiliation: School of Biological Sciences, University of Bristol, Woodland Road, UK. mark.viney@bristol.ac.uk
authors.forename: M E
authors.initials: ME
authors.lastname: Viney
authors.forename: F J
authors.initials: FJ
authors.lastname: Thompson
authors.forename: M
authors.initials: M
authors.lastname: Crook
mesh_terms: D000818:Animals; D005075:Biological Evolution; D017173:Caenorhabditis elegans / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D006790:Host-Parasite Interactions; D007814:Larva; D009348:Nematoda / Q000378:metabolism*; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta