Question

Complete nondisjunction during the first meiotic division would result in which of the following gametes at the end of meiosis II?

A) Homozygous diploid gametes
B) Heterozygous diploid gametes
C) Nullisomic gametes
D) Trisomic gametes

Answer 1

During meiosis I, nondisjunction can result in two gametes lacking a particular chromosome and two gametes having two copies. During meiosis II, nondisjunction can result in one gamete lacking a chromosome, two gametes having one copy, and one gamete having two copies.

Step-by-step explanation:

Nondisjunction can occur during either meiosis I or II. If homologous chromosomes fail to separate during meiosis I, two gametes will lack the particular chromosome, while two gametes will have two copies of the chromosome. On the other hand, if sister chromatids fail to separate during meiosis II, one gamete will lack the chromosome, two gametes will have one copy of the chromosome, and one gamete will have two copies of the chromosome.