in particular , we have generated in the chick wing bud concentration gradients of the morphogenetically active retinoid ttnpb , ( e ) -4- [ 2- ( 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl ) -1-prope nyl ] benzoic acid , a synthetic vitamin a compound .
C0035339
retinoid
C0042839
vitamin a