Using the SERV Applet to Detect Tandem Repeats in DNA Sequences and to Predict Their Variability.

INTRODUCTIONTandem repeats (satellite repeats) are short stretches of DNA that are repeated head-to-tail. Tandem repeats mutate at rates that are between 100- and 10,000-fold greater than normal (point) mutation rates in the rest of the genome. As a consequence of these frequent mutation events, "homologous" tandem repeats in closely related species, strains, or even individuals in the same population often contain a different number of repeat units. This heterogeneity is extensively used in today's molecular forensics and genotyping research. However, while all repeats are unstable, precise mutation rates vary greatly between different repeat loci. This implies that not all tandem repeats are suited as markers for forensics, genotyping, or putative hypervariable functional modules. The SERV ("Sequence-Based Estimation of Repeats Variability") applet enables finding repeats in DNA sequences and estimating their variability. Hence, it can be used to select repeats that are suitable markers for genotyping or interesting candidates for functional studies.