RESTseq - example of a library sequenced on a Ion Torrent - example of a very bad run of a RESTseq library

RESTseq - example of a library sequenced on a Ion Torrent - example of a very bad run of a RESTseq library. The second (larger fragments) peak are concatemers which arose during PCR amplification (overamplification with too many cycles). Due to overloading, the quality drops and many fragments are not read completely (shorter/incomplete reads). This can be avoided by carefully choosing appopriate (low) number of PCR cycles, or by performing a size selection to cut out longer concatemers.