Editing Germline mutation (section)

=== TALEN editing ===
The [[Transcription activator-like effector nuclease|TALEN]] (transcription activator-like effector nucleases) genome editing system is used to induce a double-stranded DNA break at a specific locus in the genome, which can then be used to mutate or repair the DNA sequence.<ref name=":7">{{cite journal | vauthors = Bedell VM, Wang Y, Campbell JM, Poshusta TL, Starker CG, Krug RG, Tan W, Penheiter SG, Ma AC, Leung AY, Fahrenkrug SC, Carlson DF, Voytas DF, Clark KJ, Essner JJ, Ekker SC | title = In vivo genome editing using a high-efficiency TALEN system | journal = Nature | volume = 491 | issue = 7422 | pages = 114–8 | date = November 2012 | pmid = 23000899 | doi = 10.1038/nature11537 | pmc=3491146| bibcode = 2012Natur.491..114B }}</ref> It functions by using a specific repeated sequence of an amino acid that is 33-34 amino acids in length.<ref name=":7" /> The specificity of the DNA binding site is determined by the specific amino acids at positions 12 and 13 (also called the Repeat Variable Diresidue (RVD)) of this tandem repeat, with some RVDs showing a higher specificity for specific amino acids over others.<ref>{{cite journal | vauthors = Nemudryi AA, Valetdinova KR, Medvedev SP, Zakian SM | title = TALEN and CRISPR/Cas Genome Editing Systems: Tools of Discovery | journal = Acta Naturae | volume = 6 | issue = 3 | pages = 19–40 | date = July 2014 | pmid = 25349712 | pmc = 4207558 | doi = 10.32607/20758251-2014-6-3-19-40 }}</ref> Once the DNA break is initiated, the ends can either be joined with NHEJ that induces mutations, or by HDR that can fix mutations.<ref name=":6" />