A Likelihood Model for Linkage Analysis of Genetic Traits

Linkage analysis is one of the major approaches for genetic studies of human diseases, for mapping putative genes or studying relationships between loci. Many of the existing methods use identity by descent data, or a particular familial structure, which may not be fully available in some practices. Here we propose a likelihood model for linkage analysis with pedigrees, along with segregation and regressive analysis. Without requiring identity by descent data, this model can be used for both quantitative and qualitative traits to study trait-trait linkage with/without observed genotypes, or trait-marker linkage with observed marker genotype, which include sib pair analysis as a special case. This model is applied to a real data example for illustration.