A man with a genetic disorder marries a normal woman. They have three daughter and five sons. All the daughters were inherited the disease and sons were normal. The gene of this diseases is:
Sex-linked dominant
Sex-linked diseases are inherited through one of the sex chromosomes, which are the X and Y chromosomes.
Dominant inheritance occurs when an abnormal gene from one parent can cause a disease, even though a matching gene from the other parent is normal. The abnormal gene dominates the gene pair.
For an X-linked dominant disorder, if the father carries the abnormal X gene, all of his daughters will inherit the disease and none of his sons will have the disease. That is because daughters always inherit their father's X chromosome. If the mother carries the abnormal X gene, half of all their children (daughters and sons) will inherit the disease tendency.