Question

In humans, an X-linked disorder called coloboma iridia (a fissure or cleft in the iris of the eye) is a recessive trait. A couple with normal eyes has a daughter with coloboma iridia. The man sues his wife for divorce on the grounds of infidelity and refuses to support the daughter, claiming the child is not his. Can you tell from this evidence whether the husband is the father of this child?

Answer 1

Answer:

Yes, since it is a recessive trait on the X chromosome the daughter would have to receive a defective gene from both parents. Even if the mom was a carrier, the father would also have to give the gene and since the father only has 1 X chromosome, he would show the trait.