Summary measures for evaluating the evidence for linkage

Two summary measures for evaluating the evidence for linkage are the maximum lod score and the average of the likelihood function (antilod score). The average antilod score can be used to calculate an exact probability of there being no linkage. Use of subjective prior probabilities in the calculation will only influence the final conclusion in any important way if evidence from the sample is not particularly conclusive. It is shown how results from two-point analyses for linkage of the test locus with each marker locus can be easily combined to give an approximate probability of there being no linkage. Some examples using bipolar affective disorder data and marker loci are presented.