comparison of a multipoint identitybydescent method with parametric multipoint linkage analysis for mapping quantitative traits we previously developed a method of partitioning genetic variance of a quantitative trait to loci in specific chromosomal regions in this paper we compare this methodmultipoint ibd identical by descent method mimwith parametric multipoint linkage analysis mlink a simulation study was performed comparing the methods for the majorlocus mixed and twolocus models the criterion for comparisons between mim and mlink was the average lod score from multiple replicates of simulated data sets the effect of gene frequency dominance model misspecification marker spacing and informativeness are also considered in a smaller set of simulations within the context of the models examined the mim approach was found to be comparable in power with parametric multipoint linkage analysis when a parental data are unknown b the effect of the major locus is small and there is additional genetic variation or c the parameters of the majorlocus model are misspecified the performance of the mim method relative to mlink was markedly lower when the allele frequency at the trait locus was 2 versus 5 particularly for the case when parental data were assumed to be known dominance at the trait major locus as well as marker spacing and heterozygosity did not appear to have a large effect on the elod comparisons