BORDER Collies are among the most intelligent of our four-legged friends, and now a test has been launched to help breeders avoid producing pups with a condition linked to sudden blindness.

It comes after Scottish scientists discovered a change in the dogs’ genetic code.

Their findings have led to a new genetic test for a severe version of the condition – called goniodysgenesis, or gonio – to help breeders avoid producing affected pups.

Severe gonio is an inherited condition in which the dogs’ eyes do not develop properly and, in some dogs, it can lead to a disease called glaucoma, causing sudden blindness.

Researchers from the University of Edinburgh’s Roslin Institute, at the Royal (Dick) School of Veterinary Studies, collected DNA from dog saliva samples and compared those with healthy eyes to those with symptoms of severe gonio.

They identified a mutation in the gene called OLFML3 – which is involved in the early stages of development of the eyeball. All the dogs that went blind had two copies of the mutated gene.

Now several companies have developed genetic tests that spot the mutation in a dog’s DNA to help breeders avoid producing puppies at risk of going blind.

Sudden blindness was first seen in Border Collies in Australia in the late 1990s. When it first appeared in the UK – in dogs related to the Australian dogs – breeders suspected that it could have a genetic cause.

The study, published in the journal G3: Genes, Genomes, Genetics, was funded by the Dogs Trust Canine Welfare Grant programme and the Pastoral Breeds Health Foundation.

Dr Carys Pugh, of Edinburgh University, said: “We are delighted that our findings have directly led to a genetic test for this condition. We hope our research will help to reduce the number of dogs that go blind.”