Left-right asymmetry

Left-right asymmetry refers to the asymmetrical nature of the human body and other organisms, where the left and right sides are not mirror images of each other. This is a fundamental aspect of biology and developmental biology, and is crucial for the correct functioning of many biological systems.

Overview

Left-right asymmetry is a key aspect of the morphology of many organisms, including humans. It is responsible for the placement and orientation of organs such as the heart, liver, and stomach, which are not positioned symmetrically within the body. This asymmetry is established early in embryonic development and is critical for the correct functioning of these organs.

Mechanisms of left-right asymmetry

The mechanisms that establish left-right asymmetry in organisms are complex and not fully understood. However, it is known that they involve a combination of genetics, cell biology, and biophysics. Key genes involved in this process include Sonic hedgehog (Shh), Nodal, and Pitx2. These genes are expressed in a left-right asymmetric manner in the developing embryo and are thought to direct the asymmetric placement of organs.

Clinical significance

Abnormalities in left-right asymmetry can lead to a range of medical conditions, collectively known as situs inversus and heterotaxy syndrome. These conditions can result in the misplacement or malformation of organs, leading to a range of health problems.

See also

• Bilateral symmetry
• Situs inversus
• Heterotaxy syndrome