Follicular patterns during feather morphogenesis in relation to the formation of asymmetric feathers, filoplumes and bristles

The present microscopic study on follicles of regenerating feathers describes the pattern of morphogenesis responsible for the formation of symmetric and asymmetric feathers, filoplumes and bristles. Barb ridges are generated in the ventral locus of the follicle and merge into a rachis located in the dorsal side after helicoidal growth along the ramogenic collar. Asymmetric feathers result from the elongation of rami of larger size on one side...