What are VNTRs?

• A. Repeats within coding exons that encode proteins
• B. Repeats that are identical in all people
• C. Short tandem repeats within the mitochondrial DNA
• D. Variable Number Tandem Repeats in DNA that differ among individuals

Answer: (D)

VNTRs are sections of DNA where a short sequence is repeated in tandem, and the number of repeats at a given location varies between individuals. That variability makes VNTR loci highly polymorphic, providing useful genetic markers for identity testing and forensic analysis. They’re usually in the nuclear genome (often in noncoding regions), not repeats confined to coding exons, not identical in all people, and not specific to mitochondrial DNA. The defining idea is that the number of repeats differs among individuals, which is exactly why VNTRs are used to distinguish DNA profiles.