Question

Haemophilia is caused by an X-linked recessive gene. Two parents with the normal phenotype have a haemophiliac child. Use a genetic diagram to show how this is possible. (4 marks) (X"= = normal; X¹ =gene for haemophilia)​

Answer 1

Since it is a recessive gene this means both parents must be carriers for a child to show the trait meaning both parents will be X X1.