How the Gene-Edited Beagles Were Created

Researchers at Kindred Companion Sciences used a two-step process combining CRISPR-Cas9 gene editing and somatic cell nuclear transfer (SCNT) — the same cloning technique used to create Dolly the sheep .

Step 1: CRISPR editing in cells. Scientists took skin cells (fibroblasts) from a female beagle fetus and used CRISPR-Cas9 to introduce a single-base insertion in the first exon of the Can f 1 gene. This caused a frameshift mutation that disables production of the Can f 1 protein entirely .

Step 2: Somatic cell nuclear transfer (cloning). The edited cell nuclei were inserted into enucleated dog egg cells. Of the 25 embryos created with the Can f 1 gene knockout, two developed to term in a surrogate mother dog, who gave birth to genetically identical female beagle puppies — Bailey and Alfie — in September 2024 .

The result was the first successful creation of dogs with a targeted Can f 1 knockout, published in the peer-reviewed journal The CRISPR Journal .

Confirmation Testing: Zero Detectable Allergen

Multiple lab assays confirmed the genetic modification eliminated the allergen:

• ELISA and Western blot tests on the dogs' saliva, fur, dander, and skin extracts detected zero Can f 1 protein — levels were below the limit of quantification, while unmodified dogs produced abundant Can f 1 .
• The knockout was stable and complete: no trace of the major dog allergen was found in any of the samples tested from either puppy .
• A preliminary human exposure test was also conducted: a person with known dog allergies who would normally react to dogs spent time with Bailey and Alfie and reported no allergic symptoms. His allergies did not disappear, but he had no reaction to these specific dogs because their saliva and fur simply lack the key protein .
• Both dogs have undergone regular veterinary exams showing normal growth and development with no adverse health effects as of two years of age .
• Kindred also reports that whole-genome sequencing found no unintended off-target edits .

The Limits: What This Dog Can and Cannot Do

Can f 1 is the primary dog allergen, responsible for about 60–70% of dog allergies, but dogs produce at least six other known allergens (Can f 2 through Can f 7). People allergic to non-Can f 1 allergens would still react, and experts caution that no dog can be truly 100% hypoallergenic .

Remaining Concerns Before Commercial Availability

Regulatory Approval

The FDA regulates gene-edited animals as "intentional genomic alterations" (IGAs) under a risk-based framework . Kindred has not yet received FDA approval for the edit, and the agency would need to evaluate the safety of the animals and the edit before they could be sold . The company has begun discussions with the FDA but no formal application has been approved.

Long-Term Health Monitoring

Only two dogs exist so far, and they are just two years old. Experts say the long-term health effects of knocking out Can f 1 are unknown — the protein's normal biological function in dogs has not been fully characterized . Kindred's founder has stated confidence from experiments on mice that there would be no serious consequences, but off-target effects must be ruled out over the dogs' full lifetimes .

Commercialization Challenges

• Scalability: SCNT cloning is expensive and inefficient. The company plans to breed the edited dogs naturally to create a lineage of Can f 1-free puppies, but this will take multiple generations to validate .
• Breed diversity: So far, only beagles have been edited. Adapting the approach to other breeds — or eventually to cats — would require additional R&D and new embryo transfers .
• Cost: Gene-edited puppies are expected to cost significantly more than conventional dogs, at least initially, potentially pricing out many allergy sufferers .

Ethical and Ecological Concerns

• Animal welfare: The SCNT cloning process has historically had high failure rates and raises questions regarding surrogate mothers and embryonic loss. The company reports that Bailey and Alfie are healthy and all procedures followed animal welfare regulations, but the broader ethics of creating gene-edited pets for human convenience remain debated .
• Impact on shelter animals: Bioethicist Arthur Caplan of NYU Grossman School of Medicine has cautioned that engineered allergy-free dogs could discourage people from adopting strays and shelter animals .
• Unintended ecosystem effects: Introducing gene-edited animals into the breeding population could have unknown long-term consequences, and some ethicists question whether creating "designer" pets for allergy relief opens the door to less defensible edits .

Timeline

Most experts estimate it will take several more years — possibly 5–10 — of further safety studies, FDA review, and breeding scale-up before allergy-free gene-edited dogs are commercially available to the public . Kindred itself has stated it has no commercial availability date to announce .

How the Gene-Edited Beagles Were Created

Researchers at Kindred Companion Sciences used a two-step process combining CRISPR-Cas9 gene editing and somatic cell nuclear transfer (SCNT) — the same cloning technique used to create Dolly the sheep .

Step 1: CRISPR editing in cells. Scientists took skin cells (fibroblasts) from a female beagle fetus and used CRISPR-Cas9 to introduce a single-base insertion in the first exon of the Can f 1 gene. This caused a frameshift mutation that disables production of the Can f 1 protein entirely .

Step 2: Somatic cell nuclear transfer (cloning). The edited cell nuclei were inserted into enucleated dog egg cells. Of the 25 embryos created with the Can f 1 gene knockout, two developed to term in a surrogate mother dog, who gave birth to genetically identical female beagle puppies — Bailey and Alfie — in September 2024 .

The result was the first successful creation of dogs with a targeted Can f 1 knockout, published in the peer-reviewed journal The CRISPR Journal .

Confirmation Testing: Zero Detectable Allergen

Multiple lab assays confirmed the genetic modification eliminated the allergen:

• ELISA and Western blot tests on the dogs' saliva, fur, dander, and skin extracts detected zero Can f 1 protein — levels were below the limit of quantification, while unmodified dogs produced abundant Can f 1 .
• The knockout was stable and complete: no trace of the major dog allergen was found in any of the samples tested from either puppy .
• A preliminary human exposure test was also conducted: a person with known dog allergies who would normally react to dogs spent time with Bailey and Alfie and reported no allergic symptoms. His allergies did not disappear, but he had no reaction to these specific dogs because their saliva and fur simply lack the key protein .
• Both dogs have undergone regular veterinary exams showing normal growth and development with no adverse health effects as of two years of age .
• Kindred also reports that whole-genome sequencing found no unintended off-target edits .

The Limits: What This Dog Can and Cannot Do

Can f 1 is the primary dog allergen, responsible for about 60–70% of dog allergies, but dogs produce at least six other known allergens (Can f 2 through Can f 7). People allergic to non-Can f 1 allergens would still react, and experts caution that no dog can be truly 100% hypoallergenic .

Remaining Concerns Before Commercial Availability

Regulatory Approval

The FDA regulates gene-edited animals as "intentional genomic alterations" (IGAs) under a risk-based framework . Kindred has not yet received FDA approval for the edit, and the agency would need to evaluate the safety of the animals and the edit before they could be sold . The company has begun discussions with the FDA but no formal application has been approved.

Long-Term Health Monitoring

Only two dogs exist so far, and they are just two years old. Experts say the long-term health effects of knocking out Can f 1 are unknown — the protein's normal biological function in dogs has not been fully characterized . Kindred's founder has stated confidence from experiments on mice that there would be no serious consequences, but off-target effects must be ruled out over the dogs' full lifetimes .

Commercialization Challenges

• Scalability: SCNT cloning is expensive and inefficient. The company plans to breed the edited dogs naturally to create a lineage of Can f 1-free puppies, but this will take multiple generations to validate .
• Breed diversity: So far, only beagles have been edited. Adapting the approach to other breeds — or eventually to cats — would require additional R&D and new embryo transfers .
• Cost: Gene-edited puppies are expected to cost significantly more than conventional dogs, at least initially, potentially pricing out many allergy sufferers .

Ethical and Ecological Concerns

• Animal welfare: The SCNT cloning process has historically had high failure rates and raises questions regarding surrogate mothers and embryonic loss. The company reports that Bailey and Alfie are healthy and all procedures followed animal welfare regulations, but the broader ethics of creating gene-edited pets for human convenience remain debated .
• Impact on shelter animals: Bioethicist Arthur Caplan of NYU Grossman School of Medicine has cautioned that engineered allergy-free dogs could discourage people from adopting strays and shelter animals .
• Unintended ecosystem effects: Introducing gene-edited animals into the breeding population could have unknown long-term consequences, and some ethicists question whether creating "designer" pets for allergy relief opens the door to less defensible edits .

Timeline

Most experts estimate it will take several more years — possibly 5–10 — of further safety studies, FDA review, and breeding scale-up before allergy-free gene-edited dogs are commercially available to the public . Kindred itself has stated it has no commercial availability date to announce .