Which type of mutation affects an entire chromosome, often altering chromosome number or structure rather than a single gene?

• A. Chromosomal mutation (chromosomal aberration)
• B. Frameshift mutation
• C. Point mutation
• D. Silent mutation

Answer: (A)

Verified step by step guidance

1. Understand the different types of mutations: point mutations affect a single nucleotide, frameshift mutations involve insertions or deletions that shift the reading frame, and silent mutations do not change the amino acid sequence despite a nucleotide change.
2. Recognize that mutations can occur at different scales: gene-level mutations affect individual genes, while chromosomal mutations affect larger segments or entire chromosomes.
3. Identify that chromosomal mutations (also called chromosomal aberrations) involve changes in chromosome number (such as nondisjunction leading to aneuploidy) or structure (such as deletions, duplications, inversions, or translocations).
4. Note that chromosomal mutations impact many genes at once because they alter large chromosome regions, unlike point or frameshift mutations which affect single genes.
5. Conclude that the mutation type affecting an entire chromosome, altering its number or structure, is a chromosomal mutation (chromosomal aberration).