title: Percentiles of the null distribution of 2 maximum lod score tests.
abstract: We here consider the null distribution of the maximum lod score (LOD-M) obtained upon maximizing over transmission model parameters (penetrance values, dominance, and allele frequency) as well as the recombination fraction. Also considered is the lod score maximized over a fixed choice of genetic model parameters and recombination-fraction values set prior to the analysis (MMLS) as proposed by Hodge et al. The objective is to fit parametric distributions to MMLS and LOD-M. Our results are based on 3,600 simulations of samples of n = 100 nuclear families ascertained for having one affected member and at least one other sibling available for linkage analysis. Each null distribution is approximately a mixture p(2)(0) + (1 - p)(2)(v). The values of MMLS appear to fit the mixture 0.20(2)(0) + 0.80chi(2)(1.6). The mixture distribution 0.13(2)(0) + 0.87chi(2)(2.8). appears to describe the null distribution of LOD-M. From these results we derive a simple method for obtaining critical values of LOD-M and MMLS.
authors.affiliation: G.H. Sergievsky Center, Columbia University, New York, NY, USA.
authors.forename: Ayse
authors.initials: A
authors.lastname: Ulgen
authors.forename: Yun Joo
authors.initials: YJ
authors.lastname: Yoo
authors.forename: Derek
authors.initials: D
authors.lastname: Gordon
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Finch
authors.forename: Nancy R
authors.initials: NR
authors.lastname: Mendell
mesh_terms: D000483:Alleles; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D016013:Likelihood Functions; D015810:Linkage Disequilibrium; D008126:Lod Score; D008957:Models, Genetic; D015233:Models, Statistical; D011995:Recombination, Genetic; D018709:Statistics, Nonparametric; D013997:Time Factors