Unlocking the Genetic Secrets of Silkworm Metamorphosis

Moulting and metamorphosis in insects are biological marvels orchestrated by chemical messengers. In domestic silkworms, these physiological processes rely heavily on ecdysteroids and juvenile hormone (JH). Yet, the genetic networks controlling these hormones remain partially shrouded in mystery. A recent study has shed light on a crucial piece of this puzzle: a gene known as CAD96CA.

Using CRISPR-Cas9 technology to edit the silkworm genome, researchers created mutants where the CAD96CA gene was 'knocked out'. The consequences were severe. The modified larvae exhibited stunted growth and, crucially for the textile industry, produced significantly less silk protein. Furthermore, the delicate process of transitioning from larva to pupa was blocked, often leading to the insect's death.

The team discovered that removing CAD96CA disrupted the synthesis and signalling pathways of vital hormones, specifically 20E (an ecdysteroid) and JH. By characterising these disruptions, the study confirms that CAD96CA is essential for successful ontogeny, offering a valuable reference for understanding the complex mechanics of insect metamorphosis.