A Bayesian approach to the direct mapping of a quantitative trait locus (QT
L), fully utilizing information from multiple linked gene markers, is prese
nted in this paper. The joint posterior distribution (a mixture distributio
n modeling the linkage between a biallelic QTL and N gene markers) is compu
tationally challenging and invites exploration via Markov chain Monte Carlo
methods. The parameter's complete marginal posterior densities are obtaine
d, allowing a diverse range of inferences. Parameters estimated include the
QTL genotype probabilities for title sires and the offspring, the allele f
requencies for the QTL, and the position and additive and dominance effects
of the QTL. The methodology is applied through simulation to a half-sib de
sign to form an outbred pedigree structure where there is an entire class o
f missing information. The capacity of the technique to accurately estimate
parameters is examined for a range of scenarios.