ABSTRACT
Multi-locus models differ from two-locus models because information other than the interval between two loci is taken into consideration. At a two-locus model level, the effect of the different genotypes of the parents for genes controlling crossover and genome rearrangement can be summarized as heterogeneity of recombination fraction between two parents. Concepts such as double crossover, crossover interference and mapping functions were all based on a three-locus model. Likelihood function for the three-locus model is the first step toward multilocus likelihood. Traditionally defined backcross and F2 populations are used as examples to illustrate the procedures to establish likelihood function for the three-locus model. The quality of a genomic map can be quantified using the confidence of estimated locus order and locus distribution on the map. Mapping functions are an important step toward a useful multi-locus model.
