A MONTE-CARLO METHOD FOR BAYESIAN-ANALYSIS OF LINKAGE BETWEEN SINGLE MARKERS AND QUANTITATIVE TRAIT LOCI .2. A SIMULATION STUDY

A Bayesian approach to the statistical mapping of Quantitative Trait L oci (QTLs) using single markers was implemented via Markov Chain Monte Carlo (MCMC) algorithms for parameter estimation and hypothesis testi ng. Parameters were estimated by marginal posterior means computed wit h a Gibbs sampler with data augmentation. Variables sampled included t he augmented data (marker-QTL genotypes, polygenic effects), the event of linkage or nonlinkage, and the parameters (allele frequencies, QTL substitution effect, recombination rate, polygenic and residual varia nces). The analysis was evaluated empirically via application to simul ated granddaughter designs consisting of 2000 sons, 20 related sires a nd their ancestors. Results obtained in this study and preliminary wor k on multiple linked markers and multiple QTLs support the usefulness of the Bayesian method for the statistical mapping of QTLs.