Related topics: genetic variation

Global data resource shows genetic diversity of chickens

A total of 174 chicken breeds are described in a publicly accessible database which scientists from the University of Göttingen and the Friedrich Loeffler Institute in Neustadt-Mariensee have built up in recent years with ...

Dark centers of chromosomes reveal ancient DNA

Geneticists exploring the dark heart of the human genome have discovered big chunks of Neanderthal and other ancient DNA. The results open new ways to study both how chromosomes behave during cell division and how they have ...

Genetic testing has a data problem. New software can help.

In recent years, the market for direct-to-consumer genetic testing has exploded. The number of people who used at-home DNA tests more than doubled in 2017, most of them in the U.S. About 1 in 25 American adults now know where ...

Research team identify genetic structure of Painted Bunting

A University of Oklahoma researcher, Andrea Contina, and his team have identified the genetic structure of the Painted Bunting, a neotropical migratory songbird, using microsatellite DNA and single nucleotide polymorphisms ...

Evolution constrains large-scale bioproduction

The transition toward sustainable biobased chemical production is important for green growth, but productivity and yield of engineered cells frequently decrease in large industry-scale fermentation. This barrier to commercialization ...

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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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