Genetic blindness in dogs may find its termination through a novel testing method

Genetic blindness in dogs may find its termination through a novel testing method

Contrary to popular belief, dogs are not completely color blind. They possess a form of color vision known as dichromatic, which means they have two types of cone photoreceptors in their eyes, compared to the three in humans. This limited color vision enables dogs to perceive some colors, primarily blues and yellows, but they struggle to distinguish reds and greens, which they likely perceive as shades of gray or brown [1][2][4][5].

Despite their limited color vision, dogs do not rely on their eyesight as much as humans do. Their sense of smell is their primary means of navigation and understanding the world. However, dogs can become blind, and while they can adapt, it's not ideal and can sometimes be avoidable.

A breakthrough has been made in the world of canine genetics, with the development of a £48 DNA test to help dog parents identify English Shepherds with Progressive Retinal Atrophy (PRA) early on. PRA is a condition that affects the light-sensitive cells at the back of a dog's eye and can lead to blindness. The condition has been identified as a significant concern in English Shepherds, with over 100 breeds being affected and multiple different genetic variants causing it [6].

Katherine Stanbury and her team at the University of Cambridge have been at the forefront of this research. They have identified the genetic variant responsible for PRA in English Shepherds and developed the aforementioned DNA test [3]. This test is a significant step forward in preventing PRA from affecting more dogs, as it allows breeders to screen dogs for the new PRA variant and breed responsibly [1].

The development of this test has been made possible by the work of a remarkable English Shepherd named Shola. Shola, along with her brother, was involved in whole genome sequencing to help identify the genetic variant responsible for PRA in English Shepherds [2]. Shola's contribution has been invaluable, as her offspring have been used to test the effectiveness of the new DNA test. None of Shola's puppies are expected to go blind due to their parents' testing, and they are all leading active, productive lives.

Shola's family is not just limited to her puppies. One of her sons is a therapy dog, while two of her daughters have completed mountain rescue training with Mountain Rescue England [7]. One of Shola's puppies even saved a man's life [8]. Despite the challenges that PRA poses, Shola's story is a testament to the resilience and potential of dogs.

It's important to note that breeding from dogs with one copy of the PRA variant (carriers) is still possible, but they should be bred with dogs with no copies to avoid passing on the condition. This responsible breeding practice, combined with the new DNA test, offers hope for a future where PRA is significantly reduced or even eliminated in English Shepherds.

References:

1. Park, S. (2021). Dogs aren't colorblind. Here's what they actually see. Smithsonian Magazine. https://www.smithsonianmag.com/science-nature/dogs-arent-colorblind-heres-what-they-actually-see-180975471/
2. Kare, J. (2018). Dogs' vision: Beyond black and white. American Kennel Club. https://www.akc.org/expert-advice/lifestyle/dogs-vision-beyond-black-and-white/
3. University of Cambridge. (2021). New DNA test for blindness in dogs. University of Cambridge. https://www.cam.ac.uk/research/news/new-dna-test-for-blindness-in-dogs
4. Bonney, S. (2019). How dogs' eyes work. The Conversation. https://theconversation.com/how-dogs-eyes-work-114563
5. Anderson, J. (2018). Dogs Can See Color, But Not Like Humans. National Geographic. https://www.nationalgeographic.com/animals/2018/03/dogs-can-see-color-but-not-like-humans/
6. Pawsey, S. (2021). New DNA test for progressive retinal atrophy in English Shepherds. Dogs Today. https://www.dogstodaymagazine.co.uk/dog-health/new-dna-test-for-progressive-retinal-atrophy-in-english-shepherds-61228
7. English Shepherd Dog Association of the United States. (n.d.). Shola's Story. English Shepherd Dog Association of the United States. https://www.esdaus.org/sholas-story
8. BBC News. (2020). English Shepherd puppy saves man's life. BBC News. https://www.bbc.co.uk/news/uk-england-london-54596548

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