Tandem repeats are short stretches of DNA that are repeated head-to-tail. These are increasingly used as markers in forensic and genotyping research. But not all tandem repeats are created equal, as they display varying rates of stability. A repeat must exhibit enough instability to generate enough heterozygosity in a population to be of use in discriminating between individuals in a population. Too much instability though makes it difficult to look over large evolutionary distances, as it becomes difficult to see relatedness between samples. To determine which repeats are useful as markers, Kevin Verstrepen’s lab at Harvard has created the SERV (“Sequence-Based Estimation of Repeats Variability”) applet, which enables finding repeats in DNA sequences and estimating their variability. First introduced in this Genome Access paper, Sequence-based estimation of minisatellite and microsatellite repeat variability, Verstrepen and colleagues have now written a guide to using the SERV Applet, available in this month’s issue of CSH Protocols.

Legendre, M., Pochet, N., Pak, T., Verstrepen, K.J. (2007). Sequence-based estimation of minisatellite and microsatellite repeat variability. Genome Research, 17(12), 1787-1796. DOI: 10.1101/gr.6554007
Legendre, M., Verstrepen, K.J. (2008). Using the SERV Applet to Detect Tandem Repeats in DNA Sequences and to Predict Their Variability. Cold Spring Harbor Protocols, 2008(2), pdb.ip50-pdb.ip50. DOI: 10.1101/pdb.ip50