Question

In a cross between a carrier female (XᴺXᶜ) and a normal male (XᴺY), what percentage of sons will be colour-blind?

Options

• 50%

• 100%

• 25%

• 75%

Answer 1

When a carrier female (XᴺXᶜ) is crossed with a normal male (XᴺY), the possible male offspring are XᴺY (normal) and XᶜY (colour-blind) in equal proportions. Therefore, 50% of sons will be colour-blind.