The formation of supernumerary structures after grafting anterior quail wing bud mesoderm of various ages into chick wing buds☆

摘要

Wedgesofanteriorquailmesodermgraftedintoposteriorslitsinthewingbudsofchickembryohostsresultintheformationofrodsandnodulesofsupernumerarycartilageinahighpercentageofcases.Identifiabledigitsdonotformunlesstheectodermisallowedtoremainonthegrafts.Controlexperimentshaveshownthatwedgesofanteriororposteriorwingmesodermplacedintohomologouslocationsofhostwingbudsproducefewornosupernumeraryskeletalstructures.Anterior-to-posteriorgraftsofstage17mesodermevokea71.4%incidenceofsupernumerarycartilage.Thispercentageincreasesto100%withstage22donormesoderm.Thepercentageofsupernumerarystructuresformeddeclinesmarkedlywithdonormesodermofstages24a€“30.Bystages35a€“36,only10%ofthegraftsresultintheformationofsupernumerarystructures.Theperiodofdeclinecoincideswiththeonsetofovertcytodifferentiationwithinthedonormesoderm.