Solve the problem: Unicornism is an X linked recessive trait. A normal man marries a normal woman and they have many children.
They have normal and unicorned boys, and all the girls are normal.
Using a punnet square and also showing the genotypes of the parents and children explain how this can happen .
Let's consider that d is a disease allele while D is a normal allele. Only individuals with two disease alleles have unicornism. Since the parents have a son with the disease and are healthy, it can be suggested that the mother is a carrier of the disease allele d. From here, the genotypes of parents and their gametes are:
Male: XDY; gametes - XD and Y;
Female: XDXd; gametes - XD and Xd.
From here, the genotypes of their children are: