A normal girl, whose mother is haemophilic marries a male with no ancestral history of haemophilia. What will

Question

A normal girl, whose mother is haemophilic marries a male with no ancestral history of haemophilia. What will be the possible phenotypes of the offsprings?

Accepted Answer

Haemophilia is a sex-linked recessive disorder . 
1. Girl's Genotype: The girl is phenotypically normal but her mother was haemophilic (). Therefore, she must have received the haemophilic allele () from her mother. Her genotype is carrier ().
2. Husband's Genotype: He has no history of the disease, so he is a normal male ().
3. Cross: Carrier Female () × Normal Male ().
4. Offspring:
   - Daughters:  (Carrier, normal phenotype) and  (Normal). All daughters are phenotypically normal.
   - Sons:  (Haemophilic) and  (Normal).
5. Conclusion: The possible phenotypes are Haemophilic sons and Normal offspring (sons and daughters). A haemophilic daughter is impossible in this cross because the father is normal and cannot contribute the required recessive allele . Assuming statements correspond to: (a) Haemophilic daughter (Impossible), (b) Haemophilic son (Possible), (c/d) Normal phenotypes (Possible), the correct combination must exclude (a). Option 4 (b and d) represents the valid phenotypic outcomes for sons (affected and normal).

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