Question

The non-disjunction, in meiosis may result is extra copy of a chromosome in a sperm cell. During which phase the above phenomenon may occur?

• A. Prophase-I, prophase-II
• B. Metaphase-I, anaphse-II
• C. Anaphase-I, anaphase-II
• D. Anaphase-I, telophase-II

Answer 1

The correct option is C Anaphase-I, anaphase-II

• At the anaphase, there is separation or segregation of the chromosomes.
• During the anaphase I, there is an individual separation of the chromosomes. During anaphase II, there is the breaking of the chromosomes from the centromere.
• This results in the proper distribution of the chromosomes in the gametes. When there is non-disjunction, there is a failure in the segregation of the chromosomes and this results in the gametes with either less or more chromosomes.
• The individual formed from the fusion of such gametes will have an extra copy of a chromosome.

Thus, the correct answer is option C.