Editing Insulin (section)

== Evolution and species distribution ==

Insulin may have originated more than a billion years ago.<ref name='Alzira'>{{cite journal |vauthors=de Souza AM, López JA |title=Insulin or insulin-like studies on unicellular organisms: a review |journal=Braz. Arch. Biol. Technol. |volume=47 |issue=6 |date=November 2004 |pages=973–81 |doi=10.1590/S1516-89132004000600017 |issn=1516-8913 |url=https://www.scielo.br/j/babt/a/dbK6VRHwStd7jfRwkJR6gvt/?format=pdf |access-date=30 June 2022|doi-access=free }}</ref> The molecular origins of insulin go at least as far back as the simplest unicellular [[eukaryotes]].<ref name='LeRoith'>{{cite journal |vauthors=LeRoith D, Shiloach J, Heffron R, Rubinovitz C, Tanenbaum R, Roth J |title=Insulin-related material in microbes: similarities and differences from mammalian insulins |journal=Canadian Journal of Biochemistry and Cell Biology |volume=63 |issue=8 |pages=839–849 |date=August 1985 |pmid=3933801 |doi=10.1139/o85-106}}</ref> Apart from animals, insulin-like proteins are also known to exist in [[fungi]] and [[protists]].<ref name='Alzira'/>

Insulin is produced by [[beta cells]] of the [[pancreatic islets]] in most vertebrates and by the [[Brockmann body]] in some [[teleost fish]].<ref>{{cite journal | vauthors = Wright JR, Yang H, Hyrtsenko O, Xu BY, Yu W, Pohajdak B | title = A review of piscine islet xenotransplantation using wild-type tilapia donors and the production of transgenic tilapia expressing a "humanized" tilapia insulin | journal = Xenotransplantation | volume = 21 | issue = 6 | pages = 485–95 | date = 2014 | pmid = 25040337 | pmc = 4283710 | doi = 10.1111/xen.12115 }}</ref> [[Cone snail]]s: ''[[Conus geographus]]'' and ''[[Conus tulipa]]'', venomous sea snails that hunt small fish, use modified forms of insulin in their venom cocktails. The insulin toxin, closer in structure to fishes' than to snails' native insulin, slows down the prey fishes by lowering their blood glucose levels.<ref>{{cite news |title= Deadly sea snail uses weaponised insulin to make its prey sluggish|url=https://www.theguardian.com/science/2015/jan/19/venomous-sea-snail-insulin-prey-conus-geographus |newspaper=The Guardian |date=19 January 2015}}</ref><ref name="pmid25605914">{{cite journal | vauthors = Safavi-Hemami H, Gajewiak J, Karanth S, Robinson SD, Ueberheide B, Douglass AD, Schlegel A, Imperial JS, Watkins M, Bandyopadhyay PK, Yandell M, Li Q, Purcell AW, Norton RS, Ellgaard L, Olivera BM | title = Specialized insulin is used for chemical warfare by fish-hunting cone snails | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 112 | issue = 6 | pages = 1743–48 | date = February 2015 | pmid = 25605914 | doi = 10.1073/pnas.1423857112 | pmc=4330763| bibcode = 2015PNAS..112.1743S | doi-access = free }}</ref>