Question

Imagine that you are a genetic counselor, and a couple planning to start a family comes to you for information. Charles was married once before, and he and his first wife had a child with cystic fibrosis. The brother of his current wife, Elaine, died of cystic fibrosis. What is the probability that Charles and Elaine will have a baby with cystic fibrosis

Answer 1

The probability that Charles and Elaine will have a baby with cystic fibrosis is 25%.

Step-by-step explanation:

The probability that Charles and Elaine will have a baby with cystic fibrosis can be determined by analyzing their family history and considering the genetic inheritance of the disease. In this case, Charles and his first wife had a child with cystic fibrosis, indicating that Charles is a carrier of the gene. Elaine's brother also had cystic fibrosis, suggesting that there is a high probability that Elaine is also a carrier.

Since cystic fibrosis is an autosomal recessive disease, both parents must be carriers of the faulty gene in order for their child to have the disease. Therefore, the probability of Charles and Elaine having a baby with cystic fibrosis would be 25%.

Answer 2

1/6

Step-by-step explanation:

Assuming the disorder is not sex linked, Charles is a carrier so he will be Ff.

His wife Elaine can be a carrier or not because her parents must have been both Ff

Possible F1 generation for her was FF, Ff, Ff and ff. She does not have the disease.

Therefore the total chance of her having FF was 1/3 whereas Ff will be 2/3

Probability of the kid having the disease will be calculated by;

(2/3×1/4) +(1/3×0)= 1/6