Actinotrichia collagens and their role in fin formation

► Actinotrichia are composed by Collagen type I, type II and actinodins. ►Col2a1b is a new form of collagen type II essential for fin formation. ► Lysyl hydroxylase 1 participates in the peculiar synthesis of actinotrichia collagen. ► Actinotrichia represent an evolutional element in fin to limb transition.