The DNA region that can accumulate mutations and influence gene regulation is most commonly referred to as:

• A. Coding DNA
• B. Satellite DNA
• C. Junk DNA
• D. Mitochondrial DNA

Answer: (C)

The key idea is that parts of the genome that don’t code for proteins can still affect how genes are turned on or off. These non-coding regions can accumulate mutations because they aren’t under the same strong pressure to preserve protein sequences, yet some of them contain regulatory elements that control transcription, such as promoters, enhancers, and silencers, or produce regulatory RNAs that influence gene expression. Because of this, non-coding DNA has the potential to influence gene regulation even as it changes over time. The term junk DNA is historically used to describe these non-coding portions, which is why it’s identified as the best fit for this concept. In contrast, coding DNA codes for proteins; satellite DNA is mostly repetitive sequences with structural roles, and mitochondrial DNA is a separate genome in mitochondria.