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single-nucleotide polymorphism

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Also known as single nucleotide variation, single nucleotide polymorphism, SNP, SNV, Snp, snp, Polymorphism, Single Nucleotide, point mutation

single nucleotide position in genomic DNA at which different sequence alternatives exist

Research

183,294 papers

via PubMed

~25 min read

Encyclopedic overview

The upper DNA molecule differs from the lower DNA molecule at a single base-pair location (a G/A polymorphism) In genetics and bioinformatics, a single-nucleotide polymorphism (SNP /snɪp/; plural SNPs /snɪps/) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population (e.g. 1% or more), many publications do not apply such a frequency threshold.

For example, a G nucleotide present at a specific location in a reference genome may be replaced by an A in a minority of individuals. The two possible nucleotide variations of this SNP – G or A – are called alleles.

Excerpted from Wikipedia’s “single-nucleotide polymorphism” article, available under the CC BY-SA 4.0 licence.