Task

In humans, polydactyly is an autosomal dominant trait (gene P) with 80 % penetrance. Both parents are heterozygous (Pp). 1) Explain penetrance and how probabilities are calculated with incomplete penetrance. 2) Calculate the probability (%) of a child with polydactyly in this family. 3) Calculate the probability (%) of a phenotypically normal child who carries the dominant gene and the overall probability of a phenotypically normal child. For each part, write out the law or method used (cross scheme, formulas, reasoning) and all calculations step by step.