How many opportunities for nondisjunction are there during meiosis?

Answer 1

Nondisjunction can occur during two key stages of meiosis: meiosis I and meiosis II.

1. During Meiosis I: Nondisjunction can happen when homologous chromosomes fail to separate properly. This leads to one daughter cell receiving both copies of a homologous chromosome pair, while the other daughter cell receives none.

2. During Meiosis II: Nondisjunction can occur when sister chromatids fail to separate properly. This can result in one daughter cell receiving both sister chromatids, while the other daughter cell receives none.

Since there are two stages where nondisjunction can happen, the overall opportunities for nondisjunction during meiosis are considered to be two: once in meiosis I and once in meiosis II.