Question

Aneuploidy is a chromosomal disorder where chromosome number is not the exact copy of its haploid set of chromosomes, due to :
(a) Substitution
(b) Addition
(c) Deletion
(d) Translocation
(e) Inversion
Choose the most appropriate answer from the options given below

• (c) and (d) only
• (d) and (e) only
• (a) and (b) only
• (b) and (c) only

Answer 1

The Correct Option is D

Aneuploidy refers to an abnormal number of chromosomes, which is not a multiple of the haploid set. This arises due to errors during chromosome segregation in meiosis.
Addition (B) and Deletion (C): These directly lead to aneuploidy. Nondisjunction, where chromosomes fail to separate correctly, can result in the addition or deletion of chromosomes in gametes.
Substitution (A): Involves replacing one nucleotide with another and does not change the chromosome number.
Translocation (D): Involves the transfer of a segment of a chromosome to a nonhomologous chromosome. While potentially causing other genetic disorders, balanced translocations do not directly cause aneuploidy because the total number of chromosomes remains the same.
Inversion (E): A segment of the chromosome is reversed end-to-end. This doesn’t change
the chromosome number.