Question

Robin is affected by an autosomal dominant disorder inherited from her mother. She is married to Chad, who is unaffected and has no history of the disorder in his family. Robin and Chad have two unaffected children. Studies suggest that for every 100 individuals who inherit mutations in the gene of interest, only 50 actually show clinical symptoms. The new mutation rate for this disorder is essentially zero. Based on this, what is the probability that their next child will present with the clinical signs of the disease? Group of answer choices

Answer 1

Answer:

The probability of the next child showing clinical signs of the disease is 1/4.

Explanation:

The above question states that Robin is affected by a mutation. This mutation may or may not be passed on to Robin's children, since the mutation is linked to a genetic factor, however, as the father of Robin's children does not have the mutation, the probability that these children will inherit the Robin mutation is 1/2 and the probability of these children presenting with the mutation symptoms also by 1/2, as presented in the question. The heritability of the mutation and its presentation of symptoms are mutually independent events. For this reason, to know the probability of Robin's next child presenting the clinical signs of the disease, we must multiply these two probabilities. The result will be 1/4.