the most common type of change in dna (molecules inside cells that carry genetic information). single nucleotide polymorphisms occur when a single nucleotide (building block of dna) is replaced with another. these changes may cause disease, and may affect how a person reacts to bacteria, viruses, drugs, and other substances. also called snp.
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出典:Wikipedia
出典:『Wikipedia』 (2011/06/03 12:10 UTC 版)
A single-nucleotide polymorphism (SNP, pronounced snip) is a DNA sequence variation occurring when a single nucleotide — A, T, C, or G — in the genome (or other shared sequence) differs between members of a biological species or paired chromosomes in an individual. For example, two sequenced DNA fragments from different individuals, AAGCCTA to AAGCTTA, contain a difference in a single nucleotide. In this case we say that there are two alleles: C and T. Almost all common SNPs have only two alleles.