Illumina/Solexa technology
The numerous cost-effective technologies were being developed for human genome resequencing that can be aligned to the reference sequence [7, 8]. The first successful technology to gain massive DNA sequencing available for resequencing was developed by Solexa (now part of Illumina, San Diego, CA, USA). The principle of the system is the method of base-by-base sequencing by synthesis, where the sheared template DNA is amplified on the flat surface slide (flow cell) and detects one base on each template per cycle with four base-specific, fluorescently labeled signals. Signals for all four fluorescent channels are collected and plotted at each position, enabling quality per scores to be derived using four-color information if desired [8]. Now, a maximum of 300 Gb for reading is available with 101 bp paired-end reading per fragment on a 1-flow cell run in the upgraded HiSeq system.