Gene editing ‘to select sex of livestock’

THE slaughter of millions of farm animals each year could become a thing of the past thanks to a scientific breakthrough.

Male chicks are culled because they cannot lay eggs and male calves suffer the same fate because they do not produce milk. But genetic engineering could ensure that only females are born instead.

It works by putting a ‘suicide gene’ in a father’s Y chromosome to stop male embryos developing beyond a cluster of cells. When researchers tested the procedure in mice, they produced female-only litters with a 100 per cent success rate.

It is likely to be at least a decade before the gene-editing technology could be deployed in agriculture.

Kent University’s Peter Ellis, co-author of a study on the breakthrough, said: ‘We have proved this is possible in principle and that could mean producing farm animals much more efficiently in the future, so that male chicks and calves do not need to be executed at only a few days old.

‘While there needs to be extensive public debate about using genetic modification in this way, the animal welfare gains are what we should be striving to achieve.’

The study, led by the Francis Crick Institute and published in the journal Nature Communications, could also help laboratory experiments, where animals of a certain sex are sometimes needed.

The gene-engineering technology did not lead to a 50 per cent decrease in the number of offspring produced and litters tended to be up to almost three quarters of the normal size.

The researchers suggested this was because animals such as mice produce more eggs than required during each ovarian cycle, allowing for a proportion to be lost during early development.