Question

# Cystic fibrosis is one of the most common autosomal recessive disorders. The carrier frequency in a...

Cystic fibrosis is one of the most common autosomal recessive disorders. The carrier frequency in a general population is 1/25. A woman who knows she is heterozygous for the mutation that causes cystic fibrosis (CF) marries a man with no family history of CF at all. What is the probability that they will produce a child that has cystic fibrosis? Suppose the couple above has a child with cystic fibrosis. What is the chance that their second child will have it? Remember to explain why.

im looking for the probabilities of each

In an autosomal recessive inheritance two copies of a disease allele are required for an individual to be susceptible to expressing the phenotype

carrier frequency = 1/25

so chance of father being carrier is =1/25

When mother and father are carriers for cystic fibrosis, the chances of child being affected is 1/4

probability that they will produce a child that has cystic fibrosis = 1/4 x 1/25 = 1/100

the chance that their second child will have it is same as the first child. Nothing has changed in terms of probability.

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