Likelihoods of multilocus DNA fingerprints in extended families

A concept for the application of complex pedigree analysis to multilocus DNA fingerprinting is described. By following this approach, the extent to which the DNA fingerprints of grandparents influence the phenotype likelihoods of their offspring was determined. It was demonstrated by simulation that approximately 90% of paternity disputes can be solved if mother, child, and paternal grandparents, instead of the putative father, are tested. If only phenotype information on a single paternal sib is allowed for, true paternity will be detected with reasonable persuasive power in up to 64% of cases. Exclusion of false paternity remains possible for 40% of cases. Finally, the analysis concept is modified by reducing the number of genotype variations considered in likelihood computations. This time-saving procedure is shown to yield sufficiently accurate likelihoods in the analysis of both simulation data and multilocus DNA fingerprints obtained in two large families.