A lod score method for detecting linkage on the X chromosome between a marker locus and a major gene locus for a quantitative character

A sequential lod-score method is proposed for detecting linkage on the X chromosome between a marker locus and the locus of a major gene influencing a quantitative trait. The method uses information from sons of doubly heterozygous mothers. The average number of families required to detect linkage is substantially less than that of the fixed sample-size method proposed by Hill.Work on this article was begun while the first author was Visiting Research Fellow, Department of Psychology and Galton laboratory, University College London, 1973–1974. Preparation of this article was supported in part by grants from the Foundations Fund for Research in Psychiatry and from the National Science Foundation.