Genetic Screening for Breeders: What It Tests For and How to Use the Results

Genetic screening tells a breeder whether an individual dog or cat carries the specific gene mutations known to cause hereditary diseases in its breed, before that animal is ever bred. The test result sorts each animal into one of three categories, clear, carrier, or affected, and that category should directly shape whether and how the animal is used in a breeding program. Skipping this step does not make the underlying genetics disappear. It just means the breeder finds out about a hereditary condition after it shows up in a litter, rather than before.

This matters most in breeds with a known, well documented set of hereditary conditions, which by now includes nearly every popular purebred dog and cat breed. A single screening panel, run once per breeding animal before its first litter, is a small cost against the alternative: producing puppies or kittens that develop a painful or shortening condition that responsible testing would have flagged in advance.

What genetic screening actually detects

A genetic screening panel looks for specific, previously identified DNA mutations known to cause disease in a given breed, not for genetic health in general. This is an important distinction: a clear result on a hip dysplasia gene panel says nothing about whether that dog will develop hip dysplasia from environmental and polygenic factors, which imaging based evaluation through OFA or PennHIP still needs to check separately.

Panels typically cover disease screening, testing for mutations linked to conditions like progressive retinal atrophy in dogs or hypertrophic cardiomyopathy in cats, and separately, parentage and trait testing, which verifies lineage and predicts physical traits like coat color rather than disease risk. Breeders often run both because they answer different questions: is this breeding pair going to reliably produce healthy offspring, and separately, does the resulting litter match the coat colors and patterns a breed standard or waiting list of buyers expects.

A screening panel is also not a one time purchase in the way a single vet visit is. Most reputable labs update their panels as researchers identify new disease causing mutations in a breed, so the list of conditions covered today is usually longer than it was even two or three years ago. Breeders working with a breed that has had a mutation identified recently should check whether their existing test results need to be supplemented rather than assuming an older panel is still complete.

Reading your results: clear, carrier, and affected

Test results for a single gene mutation come back in one of three categories, and each one means something specific for breeding decisions.

A clear or normal result means the animal carries no copies of the mutation and cannot pass the condition to offspring, regardless of what its breeding partner carries. A carrier result means the animal has one copy of the mutation but shows no symptoms itself, since the condition in question is typically recessive: one working copy of the gene is enough to prevent disease in the carrier. The risk is entirely in what happens at breeding, not in the carrier's own health. An affected result means the animal has two copies of the mutation and is likely to develop or already show the condition. Affected animals are generally excluded from breeding programs entirely, both because passing on the gene is close to guaranteed and because the animal's own quality of life is usually part of the picture by that point.

The category alone does not tell you what to do next. That depends entirely on what the breeding partner's result shows.

Choosing which tests to run for your breed

Not every test applies to every breed, and running a generic panel not built for your breed wastes money on mutations your breed does not carry at meaningful frequency. Start with your breed club or parent club's recommended testing panel, which most established breed clubs publish and update as new mutations are identified. Labs like Embark, Optimal Selection, Paw Print Genetics, and Orivet Genetic Pet Care structure their panels around breed specific recommendations rather than a one size fits all list.

Test both animals in a planned pairing well before the breeding, not after a litter is already planned or underway, since results can take several weeks to come back and a poor pairing is far easier to avoid than to undo. If you are new to structuring a breeding program around this kind of planning, our guide to responsible breeding covers the wider set of decisions genetic testing feeds into.

Building screening into your breeding program long term

A single round of testing is a start, not a finished program. Genetic testing technology continues to expand, with new mutations identified and added to panels most years, so a dog or cat cleared five years ago on the tests available then may benefit from a re-screen against the current panel before its next litter, particularly for a long producing breeding animal. Consider also archiving the raw genetic data file from the lab, not just the summary report, since panels are periodically reanalyzed as new mutations are discovered, and having the original raw data can sometimes let you check a dog retroactively against a newly added test without paying for a full new panel.

Keep detailed, permanent records of every test result alongside the pairings and litters they informed. This record does double duty: it lets you track genetic diversity across your own breeding line and avoid inadvertent inbreeding, and it gives you something concrete to hand prospective buyers. Buyers who ask about health testing are doing their own due diligence, and a breeder who can produce actual test results, not just a verbal assurance, is showing exactly the kind of transparency that separates a responsible breeding program from one that is not. For the genetics side of avoiding overly close pairings even among tested clear animals, see our piece on genetic diversity for breeders.