Genetic and experimental studies on a mutant gene (c) determining absence of heart action in embryos of the Mexican axolotl (Ambystoma mexicanum)☆

[摘要] Amutantgene,c(for“cardiaclethal”),carriedbyanadultAmbystomamexicanumimportedfromMexico,causesfailureofonsetofheartactionattheusualtimeinheartsofapparentlynormalmorphology.Thetraitappearsinapproximately25%oftheembryosofspawningsinwhichitoccurs,andisanautosomalrecessive.Headsandgillsofaffectedembryosremainsmallandamarkedascitesdevelops.Theaffectedindividualshatchandshownormalswimmingandrightingmovements.Theynevereat,anddiewithinafewdaysafterhatching.Mutantsunitedasembryosinparabiosiswithnormalmayliveindefinitely,theirheartsdisappearinginlargepartorremainingasapartofavein.Transplantsofvariousorganpreprimordiaofmutantintonormalembryosdevelopnormally.Transplantsoftheheart-formingmesodermproducenormallybeatinghearts,butinthereciprocaltransplant(normalintomutant)theheartwhichdevelopsneverbeats.Electronmicroscopy(Lemanskietal.,1970)revealsthattheheartsofmutantslackorganizedmyofibrils.Thefailureofnormaldifferentiationofthesemayresultfromlackofaninductiveinfluencebytherelatedentodermorfromaninhibitoryeffectofsometypefromthatgermlayerorotherstructures.

[学科分类] 生物科学（综合）