ALLELE-SHARING MODELS - LOD SCORES AND ACCURATE LINKAGE TESTS

Starting with a test statistic for linkage analysis based on allele sh aring, we propose an associated one-parameter model. Under general mis sing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modificatio n of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some previously suggested ap proaches to handling less than perfectly informative data can be unacc eptably conservative. Situations in which this model may not perform w ell are discussed, and an alternative model that requires additional c omputations is suggested.