Understand the differences and similarities between the most common terminologies used in genetics SNP and SNV, if any.
Genetic terminologies often need clarification even for experts, because they are confusing most of the time! SNPs, quite popular in recent times, can also create confusion when used along with SNVs or CVNs.
I did some research and came to know that many scientists and newbie students are interested to know about the differences between SNP and SNV. So I did some research, read many articles and came up with my answer.
I wrote around 500 articles on the internet and worked in molecular and cytogenetic laboratories. So I am theoretically and technically aware of things more comprehensively. Especially, in the genetic field.
In this article, I will try to compare and contrast SNP and SNV in my own way and make a clear conclusion that will clarify your confusion. So the purpose of writing this article is not to draw a clear line between SNP and SNV but to make the concept clear for you.
SNP vs SNV
SNP stands for Single Nucleotide Polymorphism while SNV stands for Single Nucleotide Variant. Both show an alteration at a single nucleotide.
However, for an SNP, the alteration should be insertion, deletion, duplication or translocation. While for SNV (as it defines a variant) there should be alternatives, for example, G instead of T, A instead of T, etc.
Google defines “polymorphism” as “several different forms” and “variant” as “something that is slightly different from something.”
So SNP can be used for individual genomes or for a population while SNV can be used for comparative analysis for example— a variation is common in one population but common in another population.
For example, beta thalassemia SNVs are common in the Sindhi population but very rare in other Indian ethnic populations.
Nonetheless, this doesn’t make sense still!
Some articles explain that the SNP is used to explain germline mutations and while addressing the population. While the SNV is used to explain somatic mutations and while comparing the populations.
In addition, some articles also said that SNPs are referred majorly for all the alterations while SVNs are referred majorly for cancer and related alterations. So to fact-check, I performed a small interesting research to learn more about this mystery.
I searched terms– single nucleotide polymorphism and single nucleotide variant in Google and various different combinations. Here is the list of combinations I searched and the number of results I found
|No. of results
|Single nucleotide polymorphism
|Single nucleotide variant
|Single nucleotide polymorphism + cancer
|Single nucleotide variant + cancer
|Single nucleotide polymorphism + somatic
|Single nucleotide variant + somatic
|Single nucleotide polymorphism + germline
|Single nucleotide variant + germline
Let me explain this data. The single nucleotide variants show more results in Google and when searched along with cancer. So this suggests that SNV can be more commonly used to show alterations associated with cancer.
However, for germline or somatic, no such concrete results are obtained. At least as per Google. These data suggest that the SNV term is quite more popular than SNP. But the interesting part came into the picture when I searched only “SNP” and “SNV” separately.
The results are shocking for me. The results show articles and search results related to single nucleotide polymorphism but something else when searched for SNV. That is something interesting. It shows that the SNP and not the SNV is the legit term to define and understand the single nucleotide change.
In population genetic study, the use of SNP and SNV is slightly different. SNV here is used for comparative analysis. For example the frequency of A>T mutation in population A is 0.03 while in population B in 0.25. While the alteration at least 1% of the population carries is categorized into an SNP.
Similarities between SNP and SNV:
- Both SNP and SNV are used to define single nucleotide change.
- The alterations can be either insertion or deletion.
- Both can be used to study single nucleotide alterations at population and individual level.
Broadly, both terminologies SNP and SNV are interchangeable. Either can be used to define a single base change in a gene, genome or population. However, SNV is now a commonly used SNP associated with cancer.
I hope you understand my opinion, either term you can use in your paper or research. That’s totally fine. No one can argue on this basis. However, keep in mind whenever you define SNP, that particular change should at least have 1% frequency in any population.
Related external resources: SNP vs SNV by Illumina.