Which statement best describes a frameshift mutation?

• A. A point mutation that changes a codon into a stop codon, prematurely terminating translation without shifting the reading frame
• B. A single-nucleotide substitution that changes one codon to a different codon but does not alter the reading frame
• C. An insertion or deletion of nucleotides in a coding sequence that is not in multiples of three, shifting the mRNA codon reading frame and often altering all downstream amino acids
• D. A chromosomal rearrangement in which a segment of one chromosome is reversed in orientation, typically without changing the codon reading frame within a gene

Answer: (C)