What is the Difference Between SNP and SNV

The main difference between SNP and SNV is that SNP is a single-base substitution that occurs in germline cells whereas SNV is a type of single nucleotide variation in the genome.

SNP and SNV are two types of single nucleotide variations that occur in the genome. Both methods are important in genotyping.

Key Areas Covered

1. What is SNP
     – Definition, Characteristics, Importance
2. What is SNV
     – Definition, Characteristics, Importance
3. Similarities Between SNP and SNV
     – Outline of Common Features
4. Difference Between SNP and SNV
     – Comparison of Key Differences

Key Terms

SNP, SNV

What is SNP

SNP or single nucleotide polymorphism is one nucleotide substitution of the germline cells. A large fraction of the population should have a single nucleotide variation in order to become a single nucleotide polymorphism. Usually, 1% of the population needs to have the variation. For instance, a specific base position of the genome contains a G nucleotide. But the minority of individuals may have the nucleotide A. Therefore, the two possible variations of the nucleotide position are G and A.

Figure 1: SNP

SNP occurs in the germline cells. The main importance of SNP is that it makes individuals susceptible to diseases. Some examples of such a disease are age-related macular degeneration. Generally, a common SNP in the CFH gene increases the risk of the disease. Another example of SNP-related disease is nonalcoholic fatty liver disease. It occurs due to the presence of an SNP in the PNPLA3 gene in the genome.

What is SNV

SNV or single nucleotide variant is a single nucleotide change in DNA sequence. SNP can be either a common SNP or a rare mutation. In addition, SNV either occurs in the germline or somatic cells. Moreover, SNV occurs in cancer. SNV is important in the designing of PCR primers for the detection of viruses.

Figure 2: Types of SNPs

Furthermore, there are two types of SNVs. SNVs in non-coding regions and SNVs in coding regions. SNVs in non-coding regions can affect the mRNA sequence and the level of gene expression. Therefore, they result in disease susceptibility. They also manifest a higher risk of cancer. There are two types of SNVs in coding regions. They are synonymous substitutions and nonsynonymous substitutions. Synonymous substitutions do not alter the amino acid sequence. On the other hand, nonsynonymous substitutions are of two types. Missense substitutions result in proteins that are malfunctioning while nonsense substitutions result in premature stop codons.  

Similarities Between SNP and SNV

• SNP and SNV are two genotyping methods that involve the detection of single nucleotide variations in the genome.
• These are detected using real-time PCR, microarrays, and next-generation sequencing.
• They are disease susceptible.

Difference Between SNP and SNV

Definition

SNP refers to a variation at a single position in a DNA sequence among individuals while SNV refers to a variation of a single nucleotide in a population’s genome.

Occurrence

SNP occurs in germline cells while SNV is a single nucleotide variation that occurs in the genome.

Correspondence

Moreover, SNP occurs in 1% of the genome while there are two types of SNVs: SNPs and rare mutations.

Conclusion

In brief, SNP or single nucleotide polymorphism is a substitution in a single nucleotide that occurs in the germline.  SNP occurs in 1% of the genome. In comparison, SNV or single nucleotide variant is a single nucleotide variation. Also, the two types of SNV are the SNPs and rare mutations. SNVs occur in both germline and somatic cells. Therefore, the main difference between SNP and SNV is their occurrence.

References:

1. “Types of Variants.” Garvan Institute of Medical Research, 14 Nov. 2018, 

Image Courtesy:

1. “Dna-SNP” By David Eccles – Own work (CC BY 4.0) via Commons Wikimedia
2. “Types of SNP new1” By MansiG123 – Own Work (CC BY-SA 4.0) via Commons Wikimedia