Question

What is the full form of RFLP? State its basic principle and mention any two important applications.

Hint:

While RFLP is highly accurate, modern genomics has largely replaced it with PCR-based markers like Short Tandem Repeats (STRs) and Single Nucleotide Polymorphisms (SNPs), which require much less DNA and are faster to analyze.

Answer 1

Step 1: Full Form of RFLP
The full form of RFLP is Restriction Fragment Length Polymorphism.

Step 2: Basic Principle of RFLP
RFLP is a molecular marker technique based on variation in the length of DNA fragments generated by digesting genomic DNA with specific restriction endonucleases:
1. Genetic Polymorphism: Individuals contain unique variations in their genomic DNA sequences due to mutations, insertions, deletions, or variable number tandem repeats (VNTRs).
2. Altering Restriction Sites: These mutations can create, destroy, or change the distance between specific restriction endonuclease recognition sites.
3. Size Variation: When genomic DNA from different individuals is digested with a specific restriction enzyme, it generates fragments of different sizes.
4. Detection: These digested fragments are separated by size using agarose gel electrophoresis, transferred to a membrane (Southern blotting), and hybridized with a labeled DNA probe to reveal unique band patterns.


Step 3: Two Important Applications of RFLP
1. DNA Fingerprinting and Forensic Science: RFLP is used in paternity testing and criminal investigations to match DNA samples found at a crime scene with potential suspects, since each individual (except identical twins) has a unique RFLP pattern.
2. Genetic Mapping and Disease Diagnosis: RFLP acts as a molecular marker to map disease-causing genes on human chromosomes. It can diagnose genetic disorders (such as sickle cell anemia or Huntington's disease) by identifying restriction site mutations linked to the disease.
Final Answer: RFLP stands for Restriction Fragment Length Polymorphism. Its principle is based on variations in DNA fragment sizes generated by digesting genomic DNA with restriction enzymes due to mutations at restriction sites. Applications include (1) forensic DNA fingerprinting and (2) mapping and diagnosing genetic diseases.