Genetically displaced sensory neurons in the head of Drosophila project via different pathways into the same specific brain regions☆

[摘要] ThesensoryprojectionpatternofhomoeoticantennalorlegtissueintheproboscisofthemutantproboscipediainDrosophilamelanogasterwasstudiedusingorthogradediffusionofcobaltchloride.Bothkindsofectopicnervefibersterminateinthenormalcenteroftheproboscisandintheantennalglomerulusofthebrain.Thesecentersareattainedbyaxonswhichmaypassviafourdifferentperipheralnerves.Incontrast,wild-typeproboscisfibersuseonlyonepathway.Dependingonthesiteofentranceintothebrain,homoeoticaxonsmayprojectintotheprobosciscenterfirst,andthenintotheantennalglomerulus,orviceversa.Consequently,thetractbetweenthesetwobrainregionsmaybefollowedinoppositedirections.Ectopiclegaxonsextendingintonormallegcentersinthethoracicganglionhavenotbeenfound.Projectionpatternsinproboscipediaarediscussedtogetherwiththoseoftheleg-likeantennainspineless-aristapedia(R.F.StockerandP.A.Lawrene,1981,Dev.Biol.82,224–237).Thefactthatdisplacedantennalandlegneuronsprojectspecificallyintonormalproboscisandantennalcentersmayreflecttheserialhomologyofantennal,leg,andproboscisneurons,andsimilarhomologyofthecorrespondingcenters.

[学科分类] 生物科学（综合）