Extensions to pedigree analysis I. Likehood calculations for simple and complex pedigrees.

A graph theoretic definition of pedigrees is given and a distinction drawn between simple and complex pedigrees. Algorithms are presented to calculate the likeihood of any kind of pedigree, assuming only segregation at a finite set of loci, nonassortative mating and no environmental correlations; multiple births and consanguineous marriages are explicity allowed for. The formulation given can lead to more powerful genetic counselling, segregation analysis and linkage analysis.