| Genetic association studies involve the exploration of relationships between certain genetic markers (e.g., a single nucleotide polymorphism, SNP) and the phenotypic value of traits. The marker is said to be associated with a trait (or traits) of interest if a certain genotype of that marker occurs alongside different phenotypic values of the trait. To date, methods for association studies have been focused on the association with a single trait at a time. In this paper, we will present a novel method that is based on a generalized quasi-likelihood scoring (GQLS) approach for testing on multiple traits simultaneously. Our quasi-likelihood scoring method for multiple traits (QLSM) also accommodates samples containing related individuals. Simulation tests evaluate the efficiency of the QLSM model. The method is applied to the analysis of Canadian Holstein Cattle data. The data set consists of ten thousand SNPs for more than eight hundred bulls with over twenty estimated breeding values (EBVs), which are considered important economic traits in animal breeding and dairy science. |
