Background: Compared to model-based approaches, nonparametric methods for quantitative trait loci mapping are more robust to deviations in distributional assumptions. In this study, we modify a nonparametric regression method and the "contrast function"- based regression method to analyze total cholesterol level in the younger cohort (the offspring generation) of the Genetic Analysis Workshop 13 simulated data set.
Results: We obtained significant evidence of linkage near four of the six non-sex-specific genes in at least 30% of the replicates.
Conclusions: The proposed nonparametric method seems to be a powerful robust alternative to distribution-based methods.