A child is born with Edwards Syndrome (Trisomy 18). Gene Z is located on chromosome 18. Which parent and which phase of meiosis did the nondisjunction event occur in?
Dad: Z¹Z²
Mom: Z²Z³
Child: Z²Z³Z³
a. Mom ; Meiosis I
b. Dad; Meiosis I
c. Dad; Meiosis II
d. Mom ; Meiosis II