Genome editing

Genome editing ^[1] is a type of genetic engineering.^[2]

DNA is inserted, replaced, or removed from a genome using artificially engineered nucleases, or "molecular scissors". The nucleases make specific double-strand breaks (DSBs) at desired places in the genome. The cell’s own mechanisms repair the induced break(s) by natural processes.

At present there are four families of engineered nucleases being used.^[3][4][5][6]

To understand the function of a gene or a protein one interferes with it in a sequence-specific way, and watches its effects on the organism. However, in some organisms it is difficult or impossible to do site-specific mutation. Therefore more indirect methods have to be used. Examples are:

• Silencing the gene of interest by short RNA interference (siRNA).^[7] Yet gene disruption by siRNA can be variable and incomplete.

• Genome editing with nucleases such as ZFN. This is different from siRNA. The engineered nuclease (the enzyme which cuts the DNA) is able to modify DNA-binding. This way it can (in principle) cut any targeted position in the genome, and introduce change in sequences for genes which cannot be specifically targeted by conventional RNAi.

Genome editing was chosen by Nature Methods as the 2011 Method of the Year.^[8] The technique is already being used, but implanting modified embryos into a woman is not yet permitted.^[9][10]

1. ↑ sometimes "genome editing with engineered nucleases" (GEEN)
2. ↑ Carey, Nessa 2019. Hacking the code of life: how gene editing will rewrite our futures. Icon books, London. ISBN 978-1-78578-625-9
3. ↑ The four types are: zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), the CRISPR/Cas system, and re-engineered homing endonucleases.
4. ↑ Esvelt, KM.; Wang, HH. (2013). "Genome-scale engineering for systems and synthetic biology". Mol Syst Biol. 9 (1): 641. doi:10.1038/msb.2012.66. PMC 3564264. PMID 23340847.
5. ↑ Tan W.S.; et al. (2012). "Precision Editing of Large Animal Genomes". Advances in Genetics. Vol. 80. pp. 37–97. doi:10.1016/B978-0-12-404742-6.00002-8. ISBN 9780124047426. PMC 3683964. PMID 23084873.
6. ↑ Puchta, H.; Fauser, F. (2013). "Gene targeting in plants: 25 years later". Int. J. Dev. Biol. 57 (6–7–8): 629–637. doi:10.1387/ijdb.130194hp. PMID 24166445.
7. ↑ Fire, Andrew; Xu, Siqun; Montgomery, Mary K.; Kostas, Steven A.; Driver, Samuel E.; Mello, Craig C. (1998). "Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans". Nature. 391 (6669): 806–811. Bibcode:1998Natur.391..806F. doi:10.1038/35888. PMID 9486653.
8. ↑ "Method of the Year 2011". Nature Methods. 9 (1): 1. 2012. doi:10.1038/nmeth.1852. PMID 22312634.
9. ↑ "Dawn of gene-editing medicine?". BBC News. 6 November 2015.
10. ↑ "Scientists get 'gene editing' go-ahead". BBC News. February 2016.