Control of integumentary patterns in the chick☆☆☆

[摘要] Toelucidatesomeoftheparametersofpatternformation,experimentsweredoneusingchickskinfromfeather,large-scale,andsmall-scaleformingregions.Piecesoffeather-formingthightractskin,isolated2daysbeforefeathersappearinovo,developnormallywhenexplantedtothechorioallantoicmembrane.Thefirstrowformsneartheedgeoftheexplant,andthesecondaryprimordiaformsequentially,establishingthenormalpatternofdiagonallyintersectingrows.Thus,boththesequential(temporal)appearanceandthespatialarrangementoffeathersarecontrolledwithintheskinitself.Normaldevelopmentalsooccursineachhalfofthetractwhentheseareseparatedbeforeexplantation.Thus,notract-specific“initiatorrow”(whichwouldnormallybecontainedonlyinthelateralhalf)isnecessaryfordevelopment.Todeterminewhetherapatternformsearlyandremainslatentuntilprimordiaappear,explantsofequalsizewereculturedfromyoungandoldembryos.Ifalatentpatternexists,theexplantsfromtheyoungerembryosshouldproduceapredictablylargernumberofprimordia,whichshouldalsobespacedclosertogether.Neitherpredictionheld,indicatingthatnolatentpatternexists.Toidentifywhichtissuecontrolsthetemporalsequenceofinitiation,pieceswereseparatedbytrypsinizationintodermisandepidermis.Thetissueswerethenrotated180°withrespecttooneanotherandrecombined.Ontheseexplants,thefirstprimordiaappearintheregionexpectedfordermalcontrol.Finally,todeterminewhichtissuecontrolsspatialarrangements,dermal-epidermalrecombinationsweremadebetweencomponentsfromdifferentregionsanddifferentagesofskin.Inallcasesthedermiscontrolsspatialarrangement.

[学科分类] 生物科学（综合）