180. Which one of the following markers is NOT routinely used for DNA fingerprinting?
A. Amplification short tandem repeats
B. Analysis of copy number variations
C. Restriction fragment length polymorphism
D. Amplification variable number tandem repeats

What Is DNA Fingerprinting?

DNA fingerprinting (also known as DNA profiling) is a technique used to identify individuals based on unique patterns in their DNA. It is widely used in forensic science, paternity testing, and genetic analysis.

Commonly Used Markers in DNA Fingerprinting

1. Short Tandem Repeats (STRs)

   • STRs are repetitive sequences of 2–6 base pairs.

   • Highly polymorphic and widely distributed throughout the genome.

   • STR analysis is the gold standard in forensic DNA profiling.

2. Variable Number Tandem Repeats (VNTRs)

   • These consist of longer sequences (10–100 base pairs).

   • Early DNA fingerprinting techniques used VNTRs, although STRs are now preferred for ease and speed.

3. Restriction Fragment Length Polymorphism (RFLP)

   • Detects variations in DNA sequence by using restriction enzymes.

   • Was one of the first methods used in DNA fingerprinting before STRs gained popularity.

Why Copy Number Variations (CNVs) Are Not Routinely Used

• Copy Number Variations involve large-scale duplications or deletions in the genome (often >1,000 base pairs).

• CNVs are not as easily amplified or standardized as STRs or VNTRs for rapid comparison.

• CNV analysis is more common in genomic studies related to disease or evolution rather than forensic identification.

Conclusion

While STRs, VNTRs, and RFLPs are routinely used in DNA fingerprinting, copy number variations (CNVs) are not commonly used due to complexity and scalability issues.

Correct Answer: B. Analysis of copy number variations