Fig. 21. A simplified linkage calculation for an autosomal dominant disease. In this idealized pedigree we assume that the disease is strictly autosomal dominant, fully penetrant, and uniform in expressivity and that there is no question of who is affected and who is not. We use the offspring to score the consequences of recombination in the meioses of the father in this pedigree. The father is the double heterozygote in this case. D represents the disease allele, d the normal allele, M one marker allele, and m the other marker allele. In Panel A, we show the cis arrangement of D and M. In Panel B, we show the trans relationship of D and M.