What is the Difference Between SNP and RFLP

The key difference between SNP and RFLP is that SNP, or Single Nucleotide Polymorphism, is a genomic variant at a single base position in the DNA, while RFLP, Restriction Fragment Length Polymorphism, is the difference in homologous DNA sequences that can be detected by the presence of fragments of different lengths after digestion of the DNA samples with specific restriction endonucleases.

DNA polymorphism refers to the existence of multiple variant forms of a particular DNA sequence that can be found among individuals or populations. Some different DNA polymorphisms include RFLP (restriction fragment length polymorphism), VNTR (variable number of tandem repeats), STR (simple tandem repeat) or SSR (simple sequence repeats), and SNP (single nucleotide polymorphism).

CONTENTS

1. Overview and Key Difference
2. What is SNP
3. What is RFLP
4. Similarities – SNP and RFLP
5. SNP vs RFLP in Tabular Form
6. Summary – SNP vs RFLP

What is SNP?

SNP (Single Nucleotide Polymorphism) is the most common type of DNA polymorphism and involves variation at a single nucleotide of a specific DNA sequence. Other DNA polymorphisms can be much larger and involve long stretches of DNA. Each SNP represents a difference in a single nucleotide. For example, an SNP may replace the nucleotide cytosine (C) with the nucleotide thymine (T) in a certain DNA sequence.

SNPs usually occur throughout a DNA in person. SNPs can occur almost once in every thousand nucleotides. This means that there are approximately 4 to 5 million SNPs in a person’s genome. To claim an SNP, a variant should be found in at least 1 percent of the population. Moreover, up to now, more than 600 million SNPs have been found in populations around the world. Furthermore, most of the SNPs have been found in the DNA between genes. These SNPs can act as biological markers that help scientists locate genes that are associated with disease and other traits. In addition, SNPs are helpful in predicting responses of individuals to certain drugs, susceptibility to environmental factors like toxins, risk of developing certain diseases, and inheritance of disease-associated genetic variants in families.

What is RFLP?

RFLP (Restriction Fragment Length Polymorphism) is defined as differences in DNA sequences among individuals at specific sites recognized by restriction enzymes. These variations produce different-length DNA fragments after digesting DNA with a restriction enzyme. RFLPs are often used as genetic markers that are normally incorporated in studies that follow the inheritance of DNA through families.

RFLP was first invented in 1984 by the English scientist Sir Alec Jeffreys. The steps involved in RFLP analysis are DNA extraction, DNA fragmentation by restriction enzymes, gel electrophoresis, and visualization of bands. The current usage of RFLP includes determining genetic diseases such as cystic fibrosis in an individual, confirming the source of a DNA sample as in paternity tests or criminal investigations, genetic mapping, and identifying a carrier of mutation that causes disease in a family. However, RFLP has several disadvantages, which include RFLP requiring a large DNA sample and the isolation procedure being laborious and time-consuming.

What are the Similarities Between SNP and RFLP?

• SNP and RFLP are two different types of DNA polymorphisms.
• Both can be used as genetic markers
• They have very important applications.
• Both have some disadvantages.

What is the Difference Between SNP and RFLP?

SNP is a genomic variant at a single base position in the DNA, while RFLP is the difference in homologous DNA sequences that can be detected by the presence of fragments of different lengths after digestion of the DNA samples with specific restriction endonucleases. Thus, this is the key difference between SNP and RFLP. Furthermore, SNP is more common than RFLP.

The below infographic presents the differences between SNP and RFLP in tabular form for side-by-side comparison.

Summary – SNP vs RFLP

DNA polymorphism is the variation in the genetic level that is inherited and present at high frequency in populations. They are very useful in genetic disease studies, paternity testing, and genetic mapping. SNP and RFLP are two different types of DNA polymorphisms. SNP is a more common type of DNA polymorphism, which involves variation at a single nucleotide in a stretch of DNA. On the other hand, RFLP is a less common type of DNA polymorphism that involves variation in the DNA sequences at sites recognized by the restriction enzymes. So, this summarizes the difference between SNP and RFLP.

Reference:

1. “Restriction Fragment Length Polymorphism.” An Overview | ScienceDirect Topics.
2. “Single Nucleotide Polymorphisms (SNPs).” Genome.Gov.

Image Courtesy:

1. “Dna-SNP” By SNP model by David Eccles (ginger) (CC BY 4.0) via Commons Wikimedia
2. “DNA Profiling – RFLP Analysis” By Phoenix_src – Own work (CC BY-SA 4.0) via Commons Wikimedia