Explain how genetic fingerprinting can be used to identify a person.

• A. The pattern of VNTRs is unique to every individual and is detected using probes
• B. It sequences the entire genome
• C. It relies on RNA expression patterns
• D. It analyzes chromosome number only

Answer: (A)

The main idea is that a person’s DNA contains highly variable regions whose lengths differ from person to person, and these differences can be read as a distinctive pattern. In genetic fingerprinting, regions called VNTRs have repeat lengths that vary among individuals. By using DNA probes that bind to these VNTR sequences, scientists generate a profile of fragment lengths that forms a banding pattern unique to each person. Because many VNTR locations are examined together, the overall fingerprint is highly discriminating and can identify an individual from a DNA sample.

This approach isn’t about sequencing the entire genome, nor does it rely on RNA expression patterns or simply counting chromosomes. The unique combination of VNTR lengths provides stable, person-specific information that remains consistent across tissues and over time, making it a reliable identifier. Note that modern methods often use shorter repeats (STRs) amplified by PCR, but the underlying concept—variable repeats producing a unique pattern detected by probes—remains the core principle.