Left-right Asymmetry in the Motor System

Left-right asymmetry: nodal points.

The striking left-right asymmetry of visceral organs is known to depend on left- and right-side-specific cascades of gene expression during early embryogenesis. Now, developmental biologists are characterizing the earliest steps in asymmetry determination that dictate the sidedness of asymmetric gene expression. The proteins and structures involved control fascinating physiological processes, s...

The embryonic origins of left-right asymmetry.

The bilaterally symmetric body plan of vertebrates features several consistent asymmetries in the placement, structure, and function of organs such as the heart, intestine, and brain. Deviations from the normal pattern result in situs inversus, isomerisms, or heterotaxia (independent randomization), which have significant clinical implications. The invariance of the left-right (LR) asymmetry of...

The Key to Left-Right Asymmetry

Establishment of left-right asymmetry in vertebrates involves cilia as essential components in the breaking of symmetry, an asymmetric signaling cascade, and a midline barrier that helps to maintain asymmetry. A new study suggests that a reaction-diffusion mechanism also plays a key role.

Left-right asymmetry in development and disease

Organisms often adopt consistent left-right (LR) asymmetric positioning and morphology of internal organs, a phenomenon known as handedness or chirality. Th e chirality of biomolecules such as sugar and DNA has been recognized for a long time, but the origins of LR asymmetry in living organisms are not yet well understood. In general, the LR patterning is considered to follow four steps: (i) LR...

Left-Right Asymmetry in Animal Embryogenesis