What term denotes a chromosome-level alteration such as deletion, duplication, inversion, or translocation?

• A. Chromosomal mutation
• B. Gene mutation
• C. Origin of Replication
• D. RNA Primer

Answer: (A)

Chromosome-level changes are called chromosomal mutations. These involve alterations in the structure or number of chromosomes themselves, not changes confined to a single gene. The four examples—deletion, duplication, inversion, and translocation—are all ways a chromosome can be rearranged or missegregated, affecting many genes at once. Deletion removes a segment; duplication adds extra copies; inversion flips a segment’s order; translocation moves a segment to a different chromosome. Because these are large-scale alterations, they’re distinct from gene mutations, which change the sequence of a single gene. Other terms in the options relate to DNA replication rather than chromosome structure.