What field studies how gene activity is regulated by factors other than changes to the DNA sequence?

• A. Genetic testing
• B. Cloning
• C. Epigenetics
• D. Recombinant DNA

Answer: (C)

Epigenetics studies how gene activity is regulated by chemical and structural changes to DNA and chromatin that do not alter the DNA sequence itself. These modifications—such as DNA methylation and histone changes—alter how tightly DNA is packaged, which genes are accessible for transcription, and thus which genes are turned on or off in a cell. Because some of these marks can be inherited through cell divisions and can respond to environment, development, or lifestyle, they can produce different expression patterns without changing the underlying sequence.

Genetic testing focuses on identifying mutations or variants in the DNA sequence, not on regulatory marks that control expression. Cloning and recombinant DNA involve creating copies or combining DNA sequences, which concern altering or reproducing DNA rather than regulating gene activity via epigenetic marks.