Gene edited sex selection may spare animal suffering - BBC News

Scientists have used gene editing technology to create female-only and male-only litters of mice.

The government is considering allowing gene editing to be used by the livestock industry in England.

The technique, which has been outlined in the academic journal Nature Communications, deactivates a gene involved with embryo development.

The system can be programmed to kick in for either male or female embryos at a very early stage of development - of between 16 and 32 cells.

The researchers believe that the technique could work on farm animals and they are in discussions to set up scientific pilot studies with the Roslin Institute near Edinburgh, which is among the world leaders in gene editing of livestock.

Dr James Turner, from the Francis Crick Institute in London, has identified 25,000 research papers published in the past five years, around 25,000 papers that required male- or female-only mice.

An independent report published earlier this week stated that animal welfare had to be at the heart of any relaxation of the rules that would allow gene editing on farm animals.

One of the report authors, Peter Stevenson, who is the chief policy adviser for Compassion in World Farming, says, that he is "wary" of gene editing, generally, because it could be used to entrench the factory farming of livestock.

"We support its use to improve animal welfare, such as ensuring that hens only produce female chicks, as this would prevent the killing of millions of unwanted male chicks in the UK each year.".

Whether a mammal is male or female is determined by the sex chromosomes.

They were able to select for sex by embedding one half of the gene editing molecule, called Crispr-Cas9, which deactivates the gene, into the mother's DNA and the other into the father's X or Y chromosome, depending on what sex was required?

If the father's half of the gene editing molecule was on his Y chromosome, once it combines with the mother's DNA containing the other half of the editing molecule, the resulting XY male embryo would have both parts of the molecule that deactivates the gene, preventing further development.