A woman is a carrier of haemophilia. Her partner is unaffected and does not carry the haemophilia allele. What is the probability that their son will have haemophilia?

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Question

A woman is a carrier of haemophilia. Her partner is unaffected and does not carry the haemophilia allele. What is the probability that their son will have haemophilia?

Accepted Answer

50% — The carrier mother has the genotype X^H X^h. All sons receive the Y chromosome from their father and one X chromosome from their mother. There is a 50% chance the son receives the X^h allele, making him haemophilic. Therefore the probability is 50%.

Answer

75%

Answer

100%

Answer

25%

Answer

50%

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