[Campbell Biology P.356] According to Figure 15.13, what are the resulting gametes if nondis... | Practice Question

According to Figure 15.13, what are the resulting gametes if nondisjunction occurs during meiosis I versus meiosis II?

  • A: Meiosis I nondisjunction results in 100% abnormal gametes (n+1, n-1); Meiosis II nondisjunction results in 50% abnormal gametes (n+1, n-1) and 50% normal gametes (n).
  • B: Meiosis I nondisjunction results in 50% abnormal gametes; Meiosis II nondisjunction results in 100% abnormal gametes.
  • C: Both processes result in 100% abnormal gametes.
  • D: Both processes result in 50% abnormal and 50% normal gametes.

Explanation

As shown in Figure 15.13, if homologous chromosomes fail to separate in Meiosis I, all four resulting gametes are abnormal two are n+1, two are n-1 . If sister chromatids fail to separate in one of the two Meiosis II cells, two of the four gametes will be normal n , while the other two will be abnormal one n+1, one n-1 .