Genomic scanning approaches that detect one locus at a time are subject to many problems in genome-wide association studies (GWAS) and quantitative trait locus (QTL) mapping. The problems include large matrix inversion, over-conservativeness for tests after Bonferroni correction and difficulty in evaluation of the total genetic contribution to a traits variance. Targeting these problems, we take a further step and investigate a multiple locus model that detects all markers simultaneously in a single model.