Homeobox genes

A homeobox is a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. Mutations in a homeobox may change large-scale anatomical features of the full-grown organism.

class of homeobox genes

thumb|Figure 1 - Mutations in the Ubx gene lead to transformation of appendages in T2 and T3 segments, resulting in a second set of wings observed in the "bithorax" phenotype.|262px Ultrabithorax (Ubx) is a homeobox gene found in insects, and is used in the regulation of patterning in morphogenesis. There are many possible products of this gene, which function as transcription factors. Ubx is used in the specification of serially homologous structures, and is used at many levels of developmental hierarchies. In Drosophila melanogaster it is expressed in the third thoracic (T3) and first abdomi

mammalian protein found in Homo sapiens

thumb|right|Fly with legs in place of antennae, caused by Antennapedia mutation thumb|right|The two Hox gene complexes in fruit flies Antennapedia (abbreviated Antp) is a Hox gene first discovered in Drosophila which controls the formation of legs during development. Loss-of-function mutations in the regulatory region of this gene result in the development of the second leg pair into ectopic antennae. By contrast gain-of-function alleles convert antennae into ectopic legs.