title: Variance-Components QTL linkage analysis of selected and non-normal samples: conditioning on trait values.
abstract: Standard variance-components quantitative trait loci (QTL) linkage analysis can produce an elevated rate of type 1 errors when applied to selected samples and non-normal data. Here we describe an adjustment of the log-likelihood function based on conditioning on trait values. This leads to a likelihood ratio test that is valid in selected samples and non-normal data, and equal in power to alternative methods for analyzing selected samples that require knowledge of the ascertainment procedure or the trait values of non-selected individuals.
authors.affiliation: Social, Genetic and Developmental Psychiatry Research Center and Department of Psychiatry, Institute of Psychiatry, Denmark Hill, London, United Kingdom. p.sham@iop.kcl.ac.uk
authors.forename: P C
authors.initials: PC
authors.lastname: Sham
authors.forename: J H
authors.initials: JH
authors.lastname: Zhao
authors.forename: S S
authors.initials: SS
authors.lastname: Cherny
authors.forename: J K
authors.initials: JK
authors.lastname: Hewitt
mesh_terms: D000704:Analysis of Variance; D003198:Computer Simulation; D008040:Genetic Linkage; D019655:Quantitative Trait, Heritable