Testing life-history pleiotropy in Caenorhabditis elegans

Much life-history theory assumes that alleles segregating in natural popula tions pleiotropically affect life-history traits. This assumption, while pl ausible, has rarely been tested directly. Here we investigate the genetic r elationship between two traits often suggested to be connected by pleiotrop y: maternal body size and fertility. We carry out a quantitative trait locu s (QTL) analysis on two isolates of the free-living nematode Caenorhabditis elegans, and identify two body size and three fertility QTLs. We find that one of the fertility QTLs colocalizes with the two body size QTLs on Chrom osome IV. Further analysis, however, shows that these QTLs are genetically separable. Thus, none of the five body size or fertility QTLs identified he re shows detectable pleiotropy for the assayed traits. The evolutionary ori gin of these QTLs, possible candidate loci, and the significance for life-h istory evolution are discussed.