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

Over the last few months (and in coming months), we’ve presented a series of protocols for genotyping and DNA isolation in a variety of model organisms. Much of this material was adapted in advance from Genetic Variation: A Laboratory Manual, which is now available from CSHL Press. It’s a difficult subject for a laboratory manual, as it’s such a rapidly advancing field, and the question when it was proposed was, is it possible to put together a manual that isn’t obsolete the moment it’s published? Read the rest of this entry »

September’s issue of CSH Protocols is upon us (my, that was a quick summer–Kurt Weill sure knew what he was talking about). We’re featuring two protocols this month, both available freely to non-subscribers (as are all of our sample protocols). The first is for generating mouse models for squamous cell carcinoma and the second is for the Oligonucleotide Ligation Assay (OLA), used for finding Single-Nucleotide Polymorphisms (SNP’s). Read the rest of this entry »

The July issue of CSH Protocols is available and features a set of articles detailing the basics for common Bioinformatics techniques (and just in time for the 4th of July, allowing me to make a “blast” pun). Read the rest of this entry »