Determination of the dorsal mesothoracic disc inDrosophila
[摘要] ExtirpationsofthedorsalmesothoracicdisccarriedoutbyPantelourisandWaddingtoninmaturelarvaeofDrosophilamelanogasterresultedintheformationofmesonotalchaetaeontheoperatedsidein4outof20cases.Thisexperimentwasrepeatedonalargescaleinbothmatureand72-hourthirdinstarlarvae.Specialattentionwaspaidtorecordingthedegreeofdiscremovalintheseoperations.Amongthe137survivorsoftheextirpations,126(92%)developednomorethanonewingandone-halfofthemesonotum.The11casesinwhichmesonotalchaetaeorwingstructuresdevelopedontheoperatedsideall(exceptanunclassifiedspecimen)belongedtoclassesinwhichpartialextirpationofthedischadbeenscored.Thestructureswhichdifferentiatedontheextirpatedsidegenerallyconformedtothespecificpresumptivepartswithinthediscanlagewhichremainedinsidethelarvalbodyinthevariousextirpationclasses.Bothobservationsindicatethatthestructureswhichdevelopedontheoperatedsidearosefromremnantsofthepartiallyextirpateddisc.IncontrasttothesuggestionofPantelourisandWaddington,evidencehasbeenpresentedwhichindicatesthatthedorsalmesothoracicdiscsdonotexistasmembersofabicentricregulativefield.Instead,itisconcludedthatdeterminationofthepairofwingdiscsasrightandleftentitiesiscomplete,notonlyinmaturelarvae,butalsoinlarvaeinthemiddleofthethirdinstar.Similarconclusionsaredrawnwithrespecttothepairedeyediscs.Amongspecimensinwhichchaetaedidnotdevelopontheoperatedside,regulationlimitedtocellproliferationandepidermalspreadingmayhaveoccurredin2individualsinthePantelourisandWaddingtonexperimentandin9casesinthepresentstudy.Thisgrowthmightbeinterpretedasahomeostaticresponseoftrichomeanlagentoabsenceofcellularmaterialfromtheoperateddiscatthetimeofnormalfusionofmesothoracicdiscproducts.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
