| Abstract: | Using sib-pairs and parent-pairs data, a quantitative trait can be tested for the existence of a major locus under the mixed model of Morton and MacLean (1974). The basic idea is to obtain the two conditional likelihoods for sib-pair differences and parent-pair differences provided that it is known which sib-pairs or parent-pairs have the same effect at the major locus. Two conditions are introduced to obtain two recursive computer algorithms that distinguish the sib-pairs or parent-pairs having the same effect at the major locus. This method has the advantage of reducing complicated computations involving maximum likelihood estimates from nuclear families. A simulation experiment is performed to illustrate the method and its results are discussed. |
