Editing DNA sequencing (section)

==== Ion Torrent semiconductor sequencing ====
{{Main|Ion semiconductor sequencing}}
Ion Torrent Systems Inc. (now owned by [[Life Technologies (Thermo Fisher Scientific)|Life Technologies]]) developed a system based on using standard sequencing chemistry, but with a novel, semiconductor-based detection system. This method of sequencing is based on the detection of [[hydrogen ion]]s that are released during the [[DNA polymerase|polymerisation]] of [[DNA]], as opposed to the optical methods used in other sequencing systems. A microwell containing a template DNA strand to be sequenced is flooded with a single type of [[nucleotide]]. If the introduced nucleotide is [[complementarity (molecular biology)|complementary]] to the leading template nucleotide it is incorporated into the growing complementary strand. This causes the release of a hydrogen ion that triggers a hypersensitive ion sensor, which indicates that a reaction has occurred. If [[homopolymer]] repeats are present in the template sequence, multiple nucleotides will be incorporated in a single cycle. This leads to a corresponding number of released hydrogens and a proportionally higher electronic signal.<ref name="rusk">{{cite journal | vauthors = Rusk N | year = 2011 | title = Torrents of sequence | journal = Nat Methods | volume = 8 | issue = 1| page = 44 | doi=10.1038/nmeth.f.330| s2cid = 41040192 | doi-access = free }}</ref>

[[File:From second to fourth-generation sequencing, illustration on TAGGCT template.svg|thumb|right| Sequencing of the TAGGCT template with IonTorrent, PacBioRS and GridION]]