A biotech company called Kindred Companion Sciences has used Crispr gene editing to create two beagle puppies, Bailey and Alfie, that lack the protein responsible for triggering most dog allergies. The breakthrough, detailed in a paper published on Wednesday in The Crispr Journal, was led by founder Matt Walker, who was inspired to pursue the project after his own allergies stopped him from owning a dog. The development matters because it could allow millions of allergy sufferers to keep dogs as pets without previous compromises, such as opting for supposedly hypoallergenic breeds that studies show often carry similarly high allergen levels.

The team used Crispr to knock out the gene producing Can f 1, the protein found in dander, hair and saliva that causes reactions in more than half of people with dog allergies, in skin cells from a female beagle. These edited cells were cloned into donor eggs, producing 25 embryos, two of which developed into healthy puppies after being implanted in a surrogate. Testing confirmed no detectable Can f 1 protein in the dogs' saliva and dander, and skin prick tests on Walker showed no allergic reaction, unlike samples from non-edited dogs. Walker has since lived with Bailey for 18 months without any allergic symptoms; the approach follows earlier, less successful attempts to create allergen-free cats using similar gene-editing techniques.