Fine mapping of multiple QTL using a reversible jump MCMC

There may be multiple QTL underlying phenotypes of a trait within a small region. The effects of closely linked QTL can be easily confounded which may negatively affect precision and accuracy of mapping of each QTL. Multiple QTL in such a small region may be considered as a single QTL, therefore the confidence interval covers all of the region. This makes fine mapping of each QTL impossible. The question is how easy multiple QTL within a small region can be accurately mapped. In this paper, we propose the use of a reversible jump MCMC (Green, 1995) in a variance component approach using combined LD and linkage (LDL) information to simultaneously map multiple QTL in a small region. The use of population wide LD can give critical information about different identity by descent (IBD) probabilities in different chromosome segments. The aim of this study is to investigate the efficiency of simultaneous mapping of multiple closely linked QTL with a proper model selection approach such as a reversible jump MCMC.