Question

In a particular cell undergoing meiosis, the first meiotic division is normal, but a chromosome undergoes nondisjunction during meiosis II. What will be the chromosome number of the four resulting gametes?

Answer 1

Nondisjunction during meiosis II typically results in two normal gametes, one gamete with an additional chromosome, and one gamete with one less chromosome.

Step-by-step explanation:

In the context of a cell undergoing meiosis, nondisjunction refers to an error in chromosome separation. When nondisjunction occurs during meiosis II, it generally results in a mix of normal and abnormal gametes. Specifically, if a chromosome fails to separate during the second meiotic division, this aberrant division would result in one gamete with an extra chromosome (n+1), one gamete lacking a chromosome (n-1), and two gametes with the normal haploid number of chromosomes (n). Therefore, in the event of nondisjunction in meiosis II, two of the resulting gametes will have the expected number of chromosomes, one will have one additional chromosome, and one will have one fewer chromosome.