LINKAGE ANALYSIS IN NUCLEAR FAMILIES .1. OPTIMALITY CRITERIA FOR AFFECTED SIB-PAIR TESTS

The affected sib-pair method can be applied to investigate linkage bet ween a marker locus and a disease. Several statistics have been propos ed to test if the observed pattern of marker alleles shared identicall y by descent (ibd) is compatible with the null hypothesis of no linkag e. Here, we consider different optimality criteria for sib-pair linkag e tests. While for recessive inherited diseases the mean test is found to be uniformly (in 8) most powerful, it can also be shown that, irre spective of the mode of inheritance, the mean test is the locally opti mal test.