Single Nucleotide Polymorphism - Use and Importance

Use and Importance

Variations in the DNA sequences of humans can affect how humans develop diseases and respond to pathogens, chemicals, drugs, vaccines, and other agents. SNPs are also critical for personalized medicine. However, their greatest importance in biomedical research is for comparing regions of the genome between cohorts (such as with matched cohorts with and without a disease) in genome-wide association studies.

The study of SNPs is also important in crop and livestock breeding programs. See SNP genotyping for details on the various methods used to identify SNPs.

SNPs are usually biallelic and thus easily assayed. A single SNP may cause a Mendelian disease. For complex diseases, SNPs do not usually function individually, rather, they work in coordination with other SNPs to manifest a disease condition as has been seen in Osteoporosis.

As of 26 June 2012 (2012-06-26), dbSNP listed 53,558,214 SNPs in humans.

SNPs have been used in genome-wide association studies (GWAS), e.g. as high-resolution markers in gene mapping related to diseases or normal traits. The knowledge of SNPs will help in understanding pharmacokinetics (PK) or pharmacodynamics, i.e. how drugs act in individuals with different genetic variants. A wide range of human diseases like cancer, infectious diseases (AIDS, leprosy, hepatitis, etc.) autoimmune, neuropsychiatric, Sickle–cell anemia, β Thalassemia and Cystic fibrosis might result from SNPs. Diseases with different SNPs may become relevant pharmacogenomic targets for drug therapy. Some SNPs are associated with the metabolism of different drugs. SNPs without an observable impact on the phenotype are still useful as genetic markers in genome-wide association studies, because of their quantity and the stable inheritance over generations.