Antennapedia

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.

[2] Recent studies have observed that down-regulation of the Antp gene in Parasteatoda tepidariorum leads to the development of a pair of ectopic legs, resulting in 10-legged mutant spiders.

[3] This suggests that spiders and insects may have separately developed strategies of the leg suppression via the evolutionary pressure of convergence.

Recent studies observed Antp and the Hox ortholog HoxC6 in Xenopus in order to further distinguish the evolution of these orthologues.