Choose the statement that best describes how nondisjunction (see Figure 13.6) can result in an aneuploid zygote.
- Nondisjunction only occurs when homologous chromosomes do not separate during meiosis I, resulting in the formation of gametes containing n+1 and n-1 chromosomes.
- Nondisjunction only occurs when sister chromatids do not separate in meiosis II, resulting in the formation of gametes containing n+1 and n-1 chromosomes.
- Nondisjunction is the failure of homologous chromosomes to separate during meiosis I or the failure of sister chromatids to separate during meiosis II, leading to the formation of n+1/n-1/n chromosomes.
- Nondisjunction occurs when the sister chromatids fail to separate during mitosis II, resulting in the formation of gametes containing n+1 and n-1/n chromosomes.