Two beagles called Alfie and Bailey lack the main protein that causes allergic reactions to dogs, thanks to CRISPR gene editing. The dogs will be 2 years old in September and show no signs of adverse effects, according to , the company behind them.
鈥淚鈥檝e lived with allergies my whole life. They prevented me and my family from ever having a dog,鈥� says Kindred co-founder Matt Walker. 鈥淎nd my wife, Maggie, has always wanted a dog.鈥� Walker previously worked as a researcher studying neuron development in worms by using CRISPR gene editing to disable specific genes. He realised it might be possible to use the technique to prevent dogs causing allergies, and founded Kindred in 2020.
How were Alfie and Bailey created?
Previous studies have found that the main allergen that triggers reactions to dogs is a protein called Can f 1. It is secreted by the tongue and by glands in the skin, so it is present both in the fur of dogs and in their saliva.
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The Kindred team took skin cells from a female beagle and used the gene-editing tool CRISPR Cas9 to mutate the Can f 1 gene 鈥� the result was an extra DNA letter at the start of the gene that shifts the way the recipe for making the Can f 1 protein is read by cells, turning it into gibberish. Once the team members had confirmed they had made the desired change without introducing unwanted mutations, they cloned the cells. Altogether, the team transferred 25 embryos to a surrogate, of which two implanted and developed to term.
Does removing this protein really prevent allergies?
Bailey is Walker鈥檚 pet dog, and he says he has no reaction to her at all. She was cavorting in the background when New Scientist spoke to him. Kindred has also showing that Can f 1 is undetectable in Alfie and Bailey, and that there are no allergic reactions to samples from them in skin-prick tests, whereas samples from normal dogs do provoke a reaction.
However, Can f 1 isn鈥檛 the only protein in dogs that can trigger allergic reactions 鈥� there are also so-called minor allergens, such as Can f 2. 鈥淚f we do find that there鈥檚 a substantial population that is still responding to the dogs, then that is something we could address,鈥� says Walker.
And could the process be harmful to dogs?
We don鈥檛 know for sure what the function of Can f 1 is, but Walker says he was confident from experiments on mice that there would be no serious consequences from deleting it. So far, both dogs appear normal and healthy, he says. 鈥淥f course, that鈥檚 something that we鈥檙e monitoring very closely, and will continue to monitor over the animals鈥� lives.鈥�
Isn鈥檛 it already possible to buy 鈥渉ypoallergenic鈥� dogs?
Some breeds, such as poodles and goldendoodles, are said to be less likely to trigger allergic reactions, but Walker says he responds just as much to the goldendoodle his parents bought after he left home as he does to any other dog. In the paper, his team shows that Can f 1 is detectable in both breeds, and that samples from them trigger reactions in skin-prick tests.
This is in line with independent evidence. The American Academy of Asthma, Allergy and Immunology says some 鈥渉ypoallergenic鈥� breeds .听
When will these dogs be commercially available?
Not for some time. Kindred first needs regulatory approval from the US Food and Drug Administration. If it gets that, it then needs to create lots more of these dogs. For each dog breed, the company will have to create a genetically diverse set of 鈥渇ounder鈥� dogs that can then be bred normally. Walker couldn鈥檛 say how many founder dogs would be required per breed.
Is it ethical to genetically engineer dogs just to prevent allergies?
鈥淲e aren鈥檛 using gene editing for novelty or some cosmetic reason,鈥� says Walker. 鈥淎llergies are a real health problem. They affect a significant portion of the population, and lead to serious conditions such as asthma triggering asthmatic attacks.鈥�
By contrast,聽conventional dog breeding is often done purely for the sake of appearance, and can introduce mutations that cause serious harm, such as those found in聽breeds like pugs聽.听Nevertheless, Kindred is altering dogs for the benefit of humans rather than the benefit of the animals themselves. In response to this, Walker says聽people discovering they are allergic to dogs is a leading reason for animals having to be rehomed.听
Is Kindred planning to gene-edit cats, too, to prevent allergies?
鈥淩ight now, we鈥檙e focused exclusively on dogs,鈥� Walker says. The main allergen in cats, called fel d 1, is encoded by two genes rather than one, so getting rid of the protein is more complex. Another company called InBio announced plans to create cats free of fel d 1 in 2022.
