title: Linkage analysis of quantitative traits: increased power by using selected samples.
abstract: Although a number of methods have been developed for linkage analysis of quantitative traits, power is relatively poor unless there is a single major locus of very large effect. Here it is demonstrated that the use of selected samples (i.e., ascertainment of a proband with an extreme score on the quantitative measure) can dramatically increase power, especially when proband selection is performed on the tail of a distribution with an infrequent recessive gene. Depending on gene action and allele frequency, selected samples permit detection of a major locus that accounts for as little as 10%-20% of the phenotypic variation. The judicious use of selected samples can make an appreciable difference in the feasibility of linkage studies for quantitative traits.
authors.affiliation: Institute for Behavioral Genetics, University of Colorado, Boulder 80309-0447.
authors.forename: G
authors.initials: G
authors.lastname: Carey
authors.forename: J
authors.initials: J
authors.lastname: Williamson
mesh_terms: D005787:Gene Frequency / Q000235:genetics; D005808:Genes, Recessive / Q000235:genetics; D008040:Genetic Linkage / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008433:Mathematics; D015233:Models, Statistical; D010641:Phenotype; D012044:Regression Analysis; D012494:Sampling Studies