Genetics

Genetic evidence shows that smoking can cause us to age faster

A study of nearly 500,000 people has shown that smoking shortens the end fragments of chromosomes in the white blood cells of our immune systems. The length of these end fragments, called telomeres, is an indicator of how ...

Genetics

Do genes determine whether you can be an endurance athlete?

For some of us, no matter how consistently we train, running never seems to get any easier—while others appear to be naturally gifted and can run for miles with ease. Part of this comes down to factors such as the kind ...

Genetics

Research examines the role of genetics in opioid use disorder

New research out of the University of Cincinnati examines the association between genetics and the presence of opioid use disorder (OUD). The study identified six single nucleotide polymorphisms (SNPs) or genetic variants ...

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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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