Polydactyly is caused by dominant allele PPP . A man with polydactyly has a mother without polydactyly. He and a woman without polydactyly plan to have three children.
Assume each birth is independent and no new mutations occur. What is the probability that exactly two of their three children will have polydactyly?
18\frac{1}{8}81
14\frac{1}{4}41
38\frac{3}{8}83
34\frac{3}{4}43
76 exam-style questions on AQA GCSE Biology 6.1 Reproduction, covering 6.1.1 Sexual and asexual reproduction, 6.1.2 Meiosis, 6.1.3 Advantages and disadvantages of sexual and asexual reproduction, 6.1.4 DNA and the genome, 6.1.5 DNA structure, 6.1.6 Genetic inheritance, 6.1.7 Inherited disorders, and 6.1.8 Sex determination. Each one has a worked solution and a mark scheme showing where the marks go.