question_answer

If a haemophilic man marries a normal lady, the of fsprings will be

A)  all haemophilic

B)  all normal

C)  haemophilic daughters

D)  haemophilic sons

Correct Answer: B

Solution :

Haemophilia is a  sex-linked  recessive disease/disorder. In female, haemophilia appears when both the sex chromosomes carry its recessive gene, ie,\[{{\text{X}}^{\text{h}}}{{\text{X}}^{\text{h}}}\text{.}\] Female, dies after birth, but if it carrier (\[\text{X}{{\text{X}}^{\text{h}}}\]) it does not die. In male,\[{{\text{X}}^{\text{h}}}\text{Y}\] is haemophilia because males are hemizygous. Therefore according to this Normal woman         Haemophilic man (Carrier (Normal (Carrier (Normal  daughter)    son)   daughter)   son) So, all daughters will be carriers (ie, normal) and sons will be normal. Thus, all offsprings will be normal.