Question

What are all possible genotypes of daughters from a cross between a carrier female (XᴴXʰ) and a normal male (XᴴY)?

Options

• XᴴXᴴ (normal) only

• XᴴXᴴ (normal) and XᴴXʰ (carrier)

• XʰXʰ (haemophilic) only

• XᴴXʰ (carrier) and XʰXʰ (haemophilic)

Answer 1

When a carrier female (XᴴXʰ) crosses with a normal male (XᴴY), daughters receive one allele from each parent. Possible genotypes are XᴴXᴴ (normal daughter) and XᴴXʰ (carrier daughter) in equal proportions. No daughter is haemophilic because they all inherit at least one dominant Xᴴ allele.