Huntington's disease is a progressive brain disorder caused by a dominant allele HHH.
A man with Huntington's disease has a mother who does not have the condition. The man's partner also does not have the condition.
The couple has four children.
Calculate the probability that all four of their children will have Huntington's disease. Give your answer as a fraction, decimal, or percentage.
66 exam-style questions on Edexcel IGCSE Biology Inheritance. Each one has a worked solution and a mark scheme showing where the marks go.