Sample pedigrees for simulated data. Circles represent females, squares represent males. Individuals with filled symbols manifest the trait under study. (a) An affected sib pair pedigree. Test sets A and B comprise 500 copies each of this pedigree with known (for set A) and unknown (set B) parental marker genotypes. (b) A multigenerational pedigree with 43 individuals. Test set C consists of 32 copies of this pedigree with all known marker genotypes. Set D consist of 4 copies of the pedigree with unknown marker genotypes for all but the last generation.