Figure 1: Single nucleotide polymorphisms (SNPs) are detected by enzymatic elongation of a primer by a SNP-complementary, fluorescently labeled ddNTP. The primer is designed to anneal one base upstream of the SNP site. Subsequent fluorescent visualization of the product reveals the incorporated nucleotide and hence the SNP genotype.

Selected References

[1] Brookes et al. (1999) The essence of SNPs. Gene 234:177.
[2] Kim et al. (2007) SNP genotyping: technologies and biomedical applications. Annual review of Biomedical Engineering 9:289.
[3] Desphande et al. (2005) Multiplexed SNP Genotyping using single-base extension (SBE) and microsphere arrays. Current protocols in Cytometry 13 (4):1.
[4] Syvänen et al. (1999) From gels to chips: Minisequencing primer extension for analysis of point mutations and single nucleotide polymorphisms. Hum. Mut. 13:10.
[5] Esteves et al. (2011) Clinical relevance of multiple single-nucleotide polymorphisms in Pneumocystis jirovecii Pneumonia: development of a multiplex PCR-single-base-extension methodology. J. Clin. Microbiol. 49 (5):1810.