Microsatellite (genetics)

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. A type of microsatellites called short tandem repeats (STRs) are often used by forensic geneticists because although the repeating sequence of base pairs of a specific microsatellite does not change from person to person, the number of times the sequence repeats does change. This allows the number of repeats of a sequence to identify a person through his/her DNA if the number of sequence repeats matches the initial DNA basis used for comparison. STRs can also eliminate a person from suspicion or reduce the suspicion of a person if he/she does not have the same number of sequence repeats as the comparate DNA . This also applies to all other organisms that have STRs. Microsatellites are often called 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.

...
Wikipedia