Definition of single nucleotide polymorphism in US English:

single nucleotide polymorphism

(also SNP)


  • A variation in a single base pair in a DNA sequence.

    • ‘Such variations, called single nucleotide polymorphisms, or SNPs, occur about every 1,000 bases in our DNA and are generally considered to be harmless.’
    • ‘In contrast, analyses of Y chromosome single nucleotide polymorphism did not provide any clear evidence for demographic expansions.’
    • ‘But 0.1 percent vary from person to person; many of those variations are known as single nucleotide polymorphisms or SNPs (pronounced ‘snips’).’
    • ‘All of these variations are single nucleotide polymorphisms rather than insertions/deletions, and only two different nucleotides were observed at each of these sites.’
    • ‘In recent years, the complete genome sequence and thousands of single nucleotide polymorphisms from laboratory mice, which are largely genetic hybrids between Mus musculus and M. domesticus, have become available.’