SAMPLING CONSIDERATIONS IN THE GATHERING AND ANALYSIS OF PEDIGREE DATA

Abstract

A general expression for the likelihood of a set of phenotypic observations on a randomly sampled pedigree, suitable for a wide variety of genetic models, was previously modified to allow for independent ascertainments via probands. Further allowance is made for the fact that a pedigree usually contains some individuals who, whatever their phenotype, could never be probands, and the limiting form of the likelihood appropriate for single ascertainment is derived. The case when the sampling frame is ill-defined is discussed, and suggestions made for how to proceed in such a case. [Applicability to genetic couseling is implicit.].