1998

Hirokawa and associates at University of Tokyo, looking at kinesins (molecular motors that transport molecules around cells) in mice, discovered monocilia that, unlike ordinary cilia (microscopic hair-like structures extending from the ends of cells), turned clockwise like propellers, creating a current flow that pumps signaling molecules secreted by the node from right to left – a molecular biological explanation of the origins of left-right asymmetry (McManus, 116-117).