A microsatellite is a brief DNA segment that is repeated several times in succession at a particular genomic site. It typically ranges in length from one to six base pairs or more. Almost always, these DNA sequences are non-coding. Microsatellites can be used as polymorphic markers to examine inheritance patterns in families or to construct a DNA fingerprint from crime scene evidence because the number of repeated segments within a microsatellite sequence differs between individuals. Higher organism genomes frequently contain microsatellites, or tandem repetitions of 1-6 bp, which frequently show significant levels of variability. Both the density of microsatellites and the frequency of different repeat motifs differ between species. Microsatellites are assumed to be neutral indicators because they are primarily found in non-coding DNA. The stepwise mutation concept is often supported by the observation that mutations in simple repeats cause the insertion or deletion of one or more repeat units.