Microsatellite

A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from 2–5 base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome; additionally, they have a higher mutation rate than other areas of DNA leading to high genetic diversity.

Microsatellites and their longer cousins, the minisatellites, together are classified as VNTR (variable number of tandem repeats) DNA. The name "satellite" refers to the early observation that centrifugation of genomic DNA in a test tube separates a prominent layer of bulk DNA from accompanying "satellite" layers of repetitive DNA. Microsatellites are often referred to as short tandem repeats (STRs) by forensic geneticists, or as simple sequence repeats (SSRs) by plant geneticists.

They are widely used for DNA profiling in kinship analysis (especially paternity testing) and in forensic identification. They are also used in genetic linkage analysis/marker assisted selection to locate a gene or a mutation responsible for a given trait or disease. Microsatellites are also used in population genetics to measure levels of relatedness between subspecies, groups and individuals.

A microsatellite is a tract of tandemly repeated (i.e. adjacent) DNA motifs that range in length from two to five nucleotides, and are typically repeated 5-50 times. For example, the sequence TATATATATA is a dinucleotide microsatellite, and GTCGTCGTCGTCGTC is a trinucleotide microsatellite (with A being Adenine, G Guanine, C Cytosine, and T Thymine). Repeat units of four and five nucleotides are referred to as tetra- and pentanucleotide motifs, respectively. Microsatellites are distributed throughout the genome. Many are located in non-coding parts of the human genome and therefore do not produce proteins, but they can also be located in regulatory regions and within the coding region.

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