Roche/454 produces longer reads than Illumina or the SOLiD System; however, the reads that are produced are fewer in number. As a result, when Roche/454 is selected as the instrument type, the only condensation method that is available is an Error Correction method that has been specifically designed to correct homopolymer errors and other base calls errors that are produced by the pyrosequencing technique. Roche/454 Error Correction works by parsing sequencing reads into shorter keywords and comparing the keywords between the reads to help determine the correct bases at the ends of each keyword. Keywords are produced by dividing the reads where a homopolymer is found and there are at least 16 bases between the homopolymers. Reads that include variations that are found at low frequencies are corrected. You can set relative and absolute frequencies for acceptable variations. The figure below is an example of indel discovery using the Condensation Tool. In this figure, a 13 bp deletion of “TGACCATACACCA” was detected at position 12243-12255.