Which of the following is an example of an epigenetic modification?

• A. Chromosome translocation
• B. Point mutation
• C. DNA methylation
• D. Gene duplication

Answer: (C)

Epigenetic modification alters how genes are expressed without changing the actual DNA sequence. DNA methylation fits this because it adds methyl groups to cytosine bases in DNA, often near gene promoters, which can repress transcription and change gene activity. This regulation can be passed to daughter cells and can respond to environmental cues, all without altering the genetic code itself. The other options involve changes to the DNA sequence or chromosome structure—chromosome translocation rearranges parts of a chromosome, a point mutation changes a nucleotide, and gene duplication increases copy number. Those are genetic changes, not epigenetic.