Single nucleotide polymorphisms, known commonly as SNPs, are the differences that appear at the level of a single nucleotide, and are one fascinating feature of genetic diversity.[1] These minute genetic variants serve as the basis for DNA matching and ethnicity estimation offered by DNA testing services like MyHeritage DNA, as well as for much of current scientific understanding about the influence of genetics on human health, evolution, and characteristics.[2] SNPs are fundamentally single-base pair modifications made to an organism's DNA.[3] They happen when a single nucleotide (A, T, C, or G) at a specific location in the genome is changed by another.[4] For instance, at a specific position, one person might have an A nucleotide whereas another person would have a C, therefore contributing to the unique variations of life on Earth.[5] For disciplines like population genetics, evolutionary biology, and medicine, an understanding of SNPs has significant ramifications.
The human genome has many SNPs, which happen about every 1,000 to 2,000 base pairs.[6] This implies that the DNA of a person has millions of SNPs. While many SNPs have little to no discernible influence on a person's characteristics or health, some can have a significant effect.[7]
SNPs can change the structure and function of proteins, which can have an impact on characteristics and health.[8] Proteins are necessary molecules that carry out numerous functions in the body, from cell signaling to enzyme catalysis.[9] An amino acid substitution brought on by an SNP in a gene encoding a protein may have an impact on the protein's structure, stability, or activity. An individual's vulnerability to specific diseases, responsiveness to treatments, or even physical traits can all be affected by these alterations.[10]
The role of SNPs in genetic genealogy and medicine
In the context of genetic genealogy, SNPs are particularly useful because they can define direct paternal lineages from deep ancestry up to historical times.[11] These small changes in the Y chromosome at a single location in one's DNA, called mutations, can help to define these lineages. Each lineage is referred to as a haplogroup. The more SNPs shared in common with another person, the more likely the individuals share a similar, and more recent, ancestry. As genetic signatures, some SNPs may be more common in particular groups or geographical areas.[12] Scientists can learn more about population evolution, genetic mixing, and migratory patterns by examining patterns of SNP distribution.
SNP mutations are rare, so sequences with SNPs tend to be passed down through generations rather than altered each generation.[13] However, because any given SNP is relatively common in a population, analysts must examine groups of SNPs to determine someone's ancestry. This is done by comparing an individual's SNP results with a genetic database of people with known ancestries.[14] Moreover, SNPs can also be used to track the inheritance of disease-associated genetic variants within families.[15] They help predict an individual's response to certain drugs, susceptibility to environmental factors such as toxins, and risk of developing diseases.
Use of SNPs in Genome-Wide Association Studies (GWAS)
SNPs have been widely used in genome-wide association studies (GWAS) to find genetic variants linked to complex traits and disorders.[16] In these investigations, the frequencies of SNPs are contrasted between people who have a specific trait or disease and people who do not. Researchers can pinpoint sections of the genome linked a specific trait or illness by detecting SNPs that are more widespread in affected people, offering important insights into the genetics of the condition.[17]
Application of SNPs in personalized medicine
SNPs are also essential for understanding individual reactions to medications and treatments in customized medicine.[18] Some SNPs can influence a person's vulnerability to harmful drug reactions or how they metabolize drugs in either a positive or negative way.[19] Healthcare practitioners can customize treatments to optimize efficacy and decrease hazards by looking at an individual's SNP profile,[20] a trend that is becoming more popular as more information is made available for physicians to make decisions or recommendations about which treatment to apply for a specific patient.
Advances in SNP research through genomic technology
High-throughput DNA sequencing is just one example of how genomic technology advancements have transformed the study of SNPs.[21] In the genome of an individual, there are dozens or even millions of SNPs that may be quickly and affordably identified and analyzed.[22] This abundance of information has created new areas for study and has allowed researchers to dive further into the connection between genetic variation and human health.
Explore more about SNPs
- The MyHeritage DNA test
- Genealogy Glossary: Common DNA Terms Explained, article by Daniella Levy on the MyHeritage Knowledge Base
- How Does DNA Matching Work? article by Daniella Levy on the MyHeritage Knowledge Base
- DNA Basics, Chapter 5: How DNA Testing Works from the MyHeritage Blog
- DNA Basics, Chapter 10: How DNA Testing Can Help You Find New Relatives from the MyHeritage Blog
- Understanding DNA Matching Technology, webinar by Ran Snir on Legacy Family Tree Webinars
References
- ↑ Syvänen, A. C. (2001). Accessing genetic variation: genotyping single nucleotide polymorphisms. Nature Reviews Genetics, 2(12), 930-942.
- ↑ Barton, N. H., & Keightley, P. D. (2002). Understanding quantitative genetic variation. Nature Reviews Genetics, 3(1), 11-21.
- ↑ Morin, P. A., Luikart, G., Wayne, R. K., & SNP Workshop Group. (2004). SNPs in ecology, evolution and conservation. Trends in ecology & evolution, 19(4), 208-216.
- ↑ Ding, C., & Jin, S. (2009). High-throughput methods for SNP genotyping. Single nucleotide polymorphisms: methods and protocols, 245-254
- ↑ McInerney, J. D. (2002). Education in a genomic world. The Journal of medicine and philosophy, 27(3), 369-390.
- ↑ Holden, A. L. (2002). The SNP consortium: summary of a private consortium effort to develop an applied map of the human genome. Biotechniques, 32(sup), S22-S26
- ↑ Newton-Cheh, C., & Hirschhorn, J. N. (2005). Genetic association studies of complex traits: design and analysis issues. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 573(1-2), 54-69.
- ↑ Ramensky, V., Bork, P., & Sunyaev, S. (2002). Human non‐synonymous SNPs: server and survey. Nucleic acids research, 30(17), 3894-3900
- ↑ Chen, Z. J., & Sun, L. J. (2009). Nonproteolytic functions of ubiquitin in cell signaling. Molecular cell, 33(3), 275-286
- ↑ Kreek, M. J., Nielsen, D. A., Butelman, E. R., & LaForge, K. S. (2005). Genetic influences on impulsivity, risk taking, stress responsivity and vulnerability to drug abuse and addiction. Nature neuroscience, 8(11), 1450-1457.
- ↑ Sampson, J. N., Kidd, K. K., Kidd, J. R., & Zhao, H. (2011, June 14). Selecting SNPs to Identify Ancestry. Annals of Human Genetics, 75(4), 539–553. https://doi.org/10.1111/j.1469-1809.2011.00656.x
- ↑ Bourret, V., Kent, M. P., Primmer, C. R., Vasemägi, A., Karlsson, S., Hindar, K., ... & Lien, S. (2013). SNP‐array reveals genome‐wide patterns of geographical and potential adaptive divergence across the natural range of Atlantic salmon (Salmo salar). Molecular ecology, 22(3), 532-551.
- ↑ VP ContempBroch Sections - National Library of Medicine. (n.d). https://www.nlm.nih.gov/exhibition/visibleproofs/education/dna/snp.pdf
- ↑ Shraga, R., Yarnall, S., Elango, S., Manoharan, A., Rodríguez, S. A., Bristow, S. L., Niknazar, M., Hoffman, D. M., Ghadir, S., Vassena, R., Chen, S., Hershlag, A., Grifo, J., & Puig, O. (n.d.). Evaluating genetic ancestry and self-reported ethnicity in the context of carrier screening - [scite report]. scite.ai. https://doi.org/10.1186/s12863-017-0570-y
- ↑ Law, W. R., Fogarty, E. A., Vester, A., & Antonellis, A. (n.d.). A genome-wide assessment of conserved SNP alleles reveals a panel of regulatory SNPs relevant to the peripheral nerve - [scite report]. scite.ai. https://doi.org/10.1186/s12864-018-4692-z
- ↑ Stranger, B. E., Stahl, E. A., & Raj, T. (2011). Progress and promise of genome-wide association studies for human complex trait genetics. Genetics, 187(2), 367-383.
- ↑ Lango, H., & Weedon, M. N. (2008). What will whole genome searches for susceptibility genes for common complex disease offer to clinical practice? Journal of Internal Medicine, 263(1), 16-27.
- ↑ Shastry, B. S. (2003). SNPs and haplotypes: genetic markers for disease and drug response. International journal of molecular medicine, 11(3), 379-382.
- ↑ Severino, G., & Del Zompo, M. (2004). Adverse drug reactions: role of pharmacogenomics. Pharmacological Research, 49(4), 363-373.
- ↑ Gupta, P. D. (2015). Pharmacogenetics, pharmacogenomics and ayurgenomics for personalized medicine: a paradigm shift. Indian journal of pharmaceutical sciences, 77(2), 135.
- ↑ Huang, X., Feng, Q., Qian, Q., Zhao, Q., Wang, L., Wang, A., ... & Han, B. (2009). High-throughput genotyping by whole-genome resequencing. Genome research, 19(6), 1068-1076.
- ↑ Rafalski, J. A. (2002). Novel genetic mapping tools in plants: SNPs and LD-based approaches. Plant science, 162(3), 329-333.