Failure to segregation of chromatids during cell division cycle which involves gain or loss of chromosome(s) is called:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Aneuploidy
Option (1) Polyploidy — Incorrect. Polyploidy is an increase in whole sets of chromosomes. It follows a failure of cytokinesis after telophase, not the loss or gain of a single chromosome.
Option (2) Euploidy — Incorrect. Euploidy means having complete sets of chromosomes (n, 2n, 3n and so on), with no single chromosome extra or missing.
Option (3) Aneuploidy — Correct. Gain or loss of one or more chromosomes after the chromatids fail to separate is aneuploidy, e.g. Down’s syndrome (trisomy 21).
Option (4) Monosomy — Incorrect. Monosomy is one kind of aneuploidy, the loss of one chromosome (as in Turner’s syndrome, 45, XO). The question also covers gain, so the broader term is needed.
NCERT Extract:
Chromosomal Disorders – …
