News tagged with single nucleotide polymorphisms

Related topics: genetic variation

Mechanism affecting risk of prostate cancer is found

A research group at Biocenter Oulu in Finland has identified a mechanism related to a transcription factor that binds much more strongly onto a particular SNP variant, thereby initiating a genetic programme which enhances ...

Jan 10, 2014
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Single-nucleotide polymorphism

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 species (or between 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.

Within a population, SNPs can be assigned a minor allele frequency — the lowest allele frequency at a locus that is observed in a particular population. This is simply the lesser of the two allele frequencies for single-nucleotide polymorphisms[1]. There are variations between human populations, so a SNP allele that is common in one geographical or ethnic group may be much rarer in another.

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