Tandem repeats can be classified as minisatellites and microsatellites. Minisatellites are generally longer in length than microsatellites (Weirdl et al., 1997). Microsatellites are small array of tandem repeats of one to six nucleotides that are interspersed throughout the genome. Microsatellite also known as simple sequence repeats (SSRs) or simple sequence length polymorphism (SSLPs) (Dhar et al., 1988).
SSRs are inherently unstable and are inherited in a Mendelian manner (Jarne and Lagoda, 1996). They are highly abundant in eukaryotes, prokaryotes and even small bacterial genomes. SSRs can be found anywhere in the genome both in coding and non-coding region and may be arise through an error in the process responsible for copying of the genome during cell division and they are unavoidable …show more content…
Different species have different frequencies of SSRs types and repeat units (Lawson and Zhang, 2006). The origin of SSRs can be equally represented in all region of genome including a coding portion that resulted in the appearance of similar amino acid repeats or tandem oligopeptide repeats in protein sequences (Katti et al., 2005). During the decade several genomes have been sequenced, leading to an increased interest in understanding the molecular mechanism involved in the origin evolution and insertion/deletion of microsatellite (Toth et al.,