Fluid-dynamical basis of the embryonic development of left-right asymmetry in vertebrates.

Experimental work in developmental biology has recently shown in mice that
fluid flow driven by rotating cilia in the node, a structure present in the
early stages of growth of vertebrate embryos, is responsible for determining
the normal development of the left--right axis, with the heart on the left of
the body, the liver on the right, and so on. The role of physics, in
particular of fluid dynamics, in the process, is one of the important questions
that remain to be answered. We show with an analysis of the fluid dynamics of
the nodal flow in the developing embryo that the leftward flow that has been
experimentally observed may be produced by the monocilia driving it being
tilted toward the posterior. We propose a model for morphogen transport and
mixing in the nodal flow, and discuss how this might initiate the development
of left--right asymmetry.