Which term describes a chromosome-level genetic alteration?

• A. Chromosomal mutation
• B. Point mutation
• C. Gene mutation
• D. Transversion

Answer: (A)

Chromosome-level genetic alteration means changes that affect entire chromosomes or large chunks of DNA, altering number or large-scale structure rather than single base pairs. This includes having an extra chromosome (like trisomy), missing a chromosome (monosomy), or big rearrangements such as deletions, duplications, inversions, or translocations that involve many genes. That’s captured by the term chromosomal mutation. In contrast, a point mutation is a single nucleotide change; a gene mutation refers to changes within a specific gene, typically smaller in scale. Transversion is a type of point mutation where one nucleotide is replaced by another from a different chemical class, not a chromosome-wide change. So the term that describes a chromosome-level genetic alteration is chromosomal mutation.