Please help! Crossing over occurs between the alleles of the genes for night blindness and color blindness. Alleles of the genes for hemophilia type A and color blindness on the same chromosome. A healthy girl’s mother is also healthy, but her father has color blindness and night blindness. This girl married a healthy guy. The probability of having children with two diseases at once is 15 percent. Determine the distance between genes A and D in morganids. There is a distance of 10 morganids between the genes for hemophilia and color blindness.