DNA ‘edit’ that could wipe out grey invaders

IT is the big, brash invasive species whose advance has left the native red squirrel clinging on for survival in areas where once it thrived.

But the march of the grey squirrels could be halted by a ‘gene drive’, say researchers at the laboratory responsible for Dolly the sheep.

The scientists say greys could be wiped out in the UK using DNA editing technology to stop them reproducing.

This would cause females to be born sterile while leaving males unaffected, meaning they could continue to spread the altered genes.

Similar technology has been used to control populations of malaria-carrying mosquitoes.

The proposal, published in The Biologist journal, has been put forward by Bruce Whitelaw, a professor in animal biotechnology at the Roslin Institute in Midlothian – where Dolly was created in 1996 – and fellow researcher Gus McFarlane.

They have already approached a team of genome engineers, population modellers, ecologists, ethicists and conservation experts to design gene drives as a potential means to eradicate grey squirrels, according

Dominant: Greys have replaced reds in many parts of the UK to the Sunday Times. ‘We are investigating strategies that could humanely control the UK grey squirrel population. One is spreading female infertility,’ Mr McFarlane said.

An alternative approach would be to alter the sex ratio, so that more males were born than females, thereby limiting the number of offspring.

The technology could be applied to other foreign species in the UK, such as muntjac deer and ring-necked parakeets. Targets in other parts of the world could include cane toads in Australia and possums in New Zealand. The researchers said that gene drives ‘may offer a more cost-effective, humane and species-specific alternative’ to existing control measures such as shooting, poisoning and trapping.

Some conservationists have backed the idea, and the Forestry Commission has welcomed the plan, although it said ‘it’s early days’.

However, Jennifer White, of People for the Ethical Treatment of Animals, said: ‘Genetically engineering humans is morally unconscionable, and doing the same to squirrels using gene-drive technology is just as reprehensible.’