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.
17-528: This is just one illustration of the tendency of organisms to exhibit variations on a theme: modulated repetition. Legs and antennae are related to one another as much as molars are to incisors, fingers are to toes, and arms are to legs. Antp also refers to a gene complex (ANT-C) in Drosophila ending with the Antp gene. It is responsible for formation and differentiation of the thoracic and head segments of
34-482: A host (plant or animal) or in a nest cell provisioned by their mothers. Apocrita has historically been split into two groups, Parasitica and Aculeata . Aculeata is a clade whose name is in standard use. "Parasitica" is not a clade, as it is paraphyletic : the clade would contain the Aculeata. "Parasitica" is therefore a rankless grouping in many present classifications, if it appears at all. Parasitica comprises
51-517: Is known that Antp -class homeobox genes play some sort of role in transcriptional processes, not all of their actions and functions have been discovered. Recent studies observed Antp and the Hox ortholog HoxC6 in Xenopus in order to further distinguish the evolution of these orthologues. HoxC6 was found to play an important role in gastrulation in the vertebrate Xenopus . However, gastrulation
68-467: Is nearly always killed. Many parasitic hymenopterans are used as biological control agents to control pests, such as caterpillars , true bugs and hoppers , flies , and weevils . Aculeata is a monophyletic group that includes those species in which the female's ovipositor is modified into a stinger to inject venom . Groups within Aculeata include the familiar ants, bees, and various types of parasitic and predatory wasps; it also includes all of
85-556: The Parasitica (containing many families of parasitoid wasps ) have been found on molecular analysis to be paraphyletic . Parasitoidism evolved once, and it is found today across most Apocritan families, though it has been secondarily lost several times. The phylogenetic tree gives a condensed overview of the phylogeny, illustrated with major groups. The sawflies are paraphyletic as the Apocrita evolved inside that group. The tree
102-408: The scutellum ; the cervix , a membrane that separates the head from the thorax; and the pleuron , a lateral sclerite of the thorax. In dragonflies and damselflies the mesothorax and metathorax are fused together to form the synthorax . In some insect pupae, like the mosquitoes ', the head and thorax can be fused in a cephalothorax . Members of suborder Apocrita (wasps, ants and bees) in
119-417: The social hymenopterans. Among the nonparasitic and nonsocial Aculeata, larvae are fed with captured prey (typically alive and paralyzed) or may be fed pollen and nectar. The social Aculeata feed their young prey ( paper wasps and hornets ), or pollen and nectar (bees), or perhaps seeds, fungi , or nonviable eggs (ants). The Apocrita contains a large number of families. Some traditional taxa such as
136-407: The "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor . The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside
153-410: The development of a pair of ectopic legs, resulting in 10-legged mutant spiders. Drosophila Antp is thought to play an important role in the role of ectopic leg or antenna placement, but not in abdominal leg suppression. However, recent research supported that leg suppression was indeed performed by Antp in arachnids. This suggests that spiders and insects may have separately developed strategies of
170-465: The early metazoan era. It is suggested that Antennapedia arose from Evx , a non- Hox family of genes. This duplication event of Evx into the Antp -class probably occurred prior to cnidarian divergence, as there are Cnidarians with Evx and without Hox class genes and vice versa. Recent studies have observed that down-regulation of the Antp gene in Parasteatoda tepidariorum leads to
187-418: The fly's body. The origin of the ancestor homeobox gene is an important aspect of the evolution of the Antp -class Hox genes . Early evolution of the Antp -class genes may have predated the divergence of cnidarians . However, the role that Antp plays in the spatial body development of cnidarians remains unclear. A widely accepted theory is that the ancestor Hox cluster containing three genes arose in
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#1732780913015204-421: The importance of the conservation of this gene cluster in the evolution of body morphology. Thorax (insect anatomy) The thorax is the midsection ( tagma ) of the hexapod body ( insects and entognathans ). It holds the head, legs , wings and abdomen . It is also called mesosoma or cephalothorax in other arthropods. It is formed by the prothorax , mesothorax and metathorax and comprises
221-403: The leg suppression via the evolutionary pressure of convergence. Arachnids' Antp gene is different from other Antp Hox clusters, suggesting that it has evolved via a divergence event leading to the development on the leg suppression function. This example suggests how the functions of homeobox genes including Antp have evolved over time to account for different lineages' needs. Although it
238-476: The majority of hymenopteran insects, its members living as parasitoids . Most species are small, with the ovipositor adapted for piercing. In some hosts, the parasitoids induce metamorphosis prematurely, and in others it is prolonged. There are even species that are hyperparasites , or parasitoids on other parasitoids. The Parasitica lay their eggs inside or on another insect (egg, larva or pupa) and their larvae grow and develop within or on that host. The host
255-414: The most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" ( petiole ) formed between the first two segments of the actual abdomen ; the first abdominal segment is fused to the thorax, and is called the propodeum . Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma (or gaster ) rather than
272-486: The order Hymenoptera have the first segment of the abdomen fused with the thorax, which is called the propodeum . The head is connected to the thorax by the occipital foramen , enabling a wide range of motion for the head. In most flying insects, the thorax allows for the use of asynchronous muscles . Apocrita Apocrita is a suborder of insects in the order Hymenoptera . It includes wasps , bees , and ants , and consists of many families. It contains
289-585: Was also a target in the Drosophila Antp gene. The anterior–posterior pattern mechanism is highly conserved in these genes, as its function in Xenopus is clear, but it is unclear why it would be a target in Drosophila . The similarities continuously observed between Hox genes in vertebrates and Drosophila suggests a complex evolutionary history of the Antp Hox gene cluster, as well as reaffirms
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