Figure 2.

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Figure 2.

The effects of mutations in homeotic genes. The first Homeobox genes discovered were Drosophila melanogaster developmental control genes that specify the identity of each body segment by controlling the identity of the organs that develop within that segment, the HOX genes. They were described as “homeotic” genes. “Homeotic” is a functional description for genes that cause homeotic transformations. All homeotic genes are transcriptional regulators. In Drosophila numerous ‘homeotic transformations’ were observed, where e.g. body parts seem to have been replaced by other. Known homeotic mutations cause the formation of an extra set of wings, or two legs at the position in the head where the antennae of a Drosophila are normally found. (a) Normal Drosophila head. (b) Drosophila homeotic mutant (Antennapaedia): antennae are replaced by legs. (c) Normal Drosophila body structure. (d) Homeotic mutant (Bithorax): segment has developed incorrectly to produce an extra set of wings. Images are courtesy of the Archives, California Institute of Technology.

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gcsp/2015/3/gcsp.2015.36.gr2.gif

Figure 2. The effects of mutations in homeotic genes. The first Homeobox genes discovered were Drosophila melanogaster developmental control genes that specify the identity of each body segment by controlling the identity of the organs that develop within that segment, the HOX genes. They were described as “homeotic” genes. “Homeotic” is a functional description for genes that cause homeotic transformations. All homeotic genes are transcriptional regulators. In Drosophila numerous ‘homeotic transformations’ were observed, where e.g. body parts seem to have been replaced by other. Known homeotic mutations cause the formation of an extra set of wings, or two legs at the position in the head where the antennae of a Drosophila are normally found. (a) Normal Drosophila head. (b) Drosophila homeotic mutant (Antennapaedia): antennae are replaced by legs. (c) Normal Drosophila body structure. (d) Homeotic mutant (Bithorax): segment has developed incorrectly to produce an extra set of wings. Images are courtesy of the Archives, California Institute of Technology. © 2015 Allouba, ElGuindy, Krishnamoorthy, Yacoub, Aguib, licensee Bloomsbury Qatar Foundation Journals.

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