Formation of supernumerary structures by the embryonic chick wing depends on the position and orientation of a graft in a host limb bud☆

[摘要] Therelationshipbetweenthepositiontransplantedinahostlimbbud,theorientationofagraftinahostlimbbud,andtheextralimbstructuresformedwasstudiedbyjuxtaposingnormallynonadjacentembryonicchickwingbudtissue.Inoneseriesoftransplantationoperations,twodifferentwedges(ectodermandmesoderm)ofstage21rightdonorposteriorwingbudtissueweretransplantedtothemiddleofahoststage20to22rightwingbudsuchthatthedorsal-ventralpolarityofthegraftandhostwerethesameorreversed.Theresultsofthesetransplantationoperationsshowthattheformationofsupernumerarylimbstructuresdependsonthepositionoforiginofthedonortissue,theanterior-posteriorpositiontransplantedinahostlimbbud,andtheorientationofthegraftinthehostlimbbud.Inasecondseriesoftransplantationoperations,therelationshipbetweentheproximodistalpositionwhereposteriordonortissueistransplantedinananteriorhostsiteandtheextrastructuresformedwasstudied.Awedgeofposteriorstage21rightwingbudtissuewastransplantedtoananteriorproximaloranteriordistalsiteofastage22to24hostrightwingbud.Theresultsofthesetransplantationoperationsshowthatwhenthedonortissueistransplantedtoananteriorproximalpositioninahostwingbud,thenlimbswithonlyaduplicatedhumerusresult,whereas,whentransplantedtoananteriordistalposition,thenlimbswithaduplicatedforearmelementandextradigitsresult.

[学科分类] 生物科学（综合）