Genes shed light on moles' ‘blindness’

The 'defects' result from genetic triggers that occur in the embryo and are not, as some have thought, a degenerative condition that starts in adulthood, they said.

Fibres that develop into the moles' lens start to grow normally but are not completed as a result of interference of two genes called PAX6 and FOXE3.

Other genes that are central to eye development also behave abnormally, the researchers found.

Under Darwinian theory, moles and other subterranean animals forego good vision in order to accentuate sensitivity to vibrations and smell that help them survive.

The study was carried out on embryos of the Iberian mole, Talpa occidentalis, which unlike other mole species has permanently closed eyes.

The paper, led by Martin Collinson of the University of Aberdeen, northeastern Scotland, appears in the British-based open-access journal BMC Biology.