Turner syndrome occurs when an individual inherits one X chromosome but lacks a second sex chromosome.

a.  Can Turner syndrome be due to nondisjunction during oogenesis, spermatogenesis, or both?  Explain.  (3 pts)

b.  If a phenotypically normal couple has a color-blind child (due to a recessive X-linked allele) with Turner syndrome, did nondisjunction occur during oogenesis or spermatogenesis in this child’s parents?  Explain your answer.  (3 pts)