Editing Homeobox (section)

== Discovery ==
[[File:Mutation Antennapedia.jpg|thumb|''Drosophila'' with the ''antennapedia'' mutant phenotype exhibit homeotic transformation of the antennae into leg-like structures on the head.|alt=]]
The existence of homeobox genes was first discovered in ''[[Drosophila]]'' by isolating the gene responsible for a homeotic transformation where legs grow from the head instead of the expected antennae. Walter Gehring identified a gene called ''[[antennapedia]]'' that caused this homeotic phenotype.<ref>{{cite journal | vauthors = Garber RL, Kuroiwa A, Gehring WJ | title = Genomic and cDNA clones of the homeotic locus Antennapedia in Drosophila | journal = The EMBO Journal | volume = 2 | issue = 11 | pages = 2027–36 | date = 1983 | pmid = 6416827 | pmc = 555405 | doi = 10.1002/j.1460-2075.1983.tb01696.x }}</ref> Analysis of ''antennapedia'' revealed that this gene contained a 180 base pair sequence that encoded a DNA binding domain, which William McGinnis termed the "homeobox".<ref>{{Cite web|url=https://embryo.asu.edu/pages/walter-jakob-gehring-1939-2014|title=Walter Jakob Gehring (1939-2014) {{!}} The Embryo Project Encyclopedia|website=embryo.asu.edu|access-date=2019-12-09|archive-date=2019-12-09|archive-url=https://web.archive.org/web/20191209223802/https://embryo.asu.edu/pages/walter-jakob-gehring-1939-2014|url-status=live}}</ref> The existence of additional ''Drosophila'' genes containing the ''antennapedia'' homeobox sequence was independently reported by Ernst Hafen, [[Michael Levine (biologist)|Michael Levine]], [[William McGinnis]], and [[Walter Jakob Gehring]] of the [[University of Basel]] in [[Switzerland]] and [[Matthew P. Scott]] and Amy Weiner of [[Indiana University (Bloomington)|Indiana University]] in [[Bloomington, Indiana|Bloomington]] in 1984.<ref>{{cite journal | vauthors = McGinnis W, Levine MS, Hafen E, Kuroiwa A, Gehring WJ | title = A conserved DNA sequence in homoeotic genes of the Drosophila Antennapedia and bithorax complexes | journal = Nature | volume = 308 | issue = 5958 | pages = 428–33 | date = 1984 | pmid = 6323992 | doi = 10.1038/308428a0 | bibcode = 1984Natur.308..428M | s2cid = 4235713 }}</ref><ref>{{cite journal | vauthors = Scott MP, Weiner AJ | title = Structural relationships among genes that control development: sequence homology between the Antennapedia, Ultrabithorax, and fushi tarazu loci of Drosophila | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 81 | issue = 13 | pages = 4115–9 | date = July 1984 | pmid = 6330741 | pmc = 345379 | doi = 10.1073/pnas.81.13.4115 | bibcode = 1984PNAS...81.4115S | doi-access = free }}</ref> Isolation of homologous genes by [[Edward M. De Robertis|Edward de Robertis]] and William McGinnis revealed that numerous genes from a variety of species contained the homeobox.<ref>{{cite journal | vauthors = Carrasco AE, McGinnis W, Gehring WJ, De Robertis EM | title = Cloning of an X. laevis gene expressed during early embryogenesis coding for a peptide region homologous to Drosophila homeotic genes | journal = Cell | volume = 37 | issue = 2 | pages = 409–414 | date = June 1984 | pmid = 6327066 | doi = 10.1016/0092-8674(84)90371-4 | s2cid = 30114443 }}</ref><ref>{{cite journal | vauthors = McGinnis W, Garber RL, Wirz J, Kuroiwa A, Gehring WJ | title = A homologous protein-coding sequence in Drosophila homeotic genes and its conservation in other metazoans | language = en | journal = Cell | volume = 37 | issue = 2 | pages = 403–8 | date = June 1984 | pmid = 6327065 | doi = 10.1016/0092-8674(84)90370-2 | s2cid = 40456645 | url = https://www.cell.com/cell/abstract/0092-8674(84)90370-2 | access-date = 2019-12-09 | archive-date = 2021-05-04 | archive-url = https://web.archive.org/web/20210504015040/https://www.cell.com/cell/fulltext/0092-8674(84)90370-2 | url-status = live }}</ref> Subsequent [[Phylogenetics|phylogenetic]] studies detailing the evolutionary relationship between homeobox-containing genes showed that these genes are present in all [[Bilateria|bilaterian]] animals.