Dominant Blue-Eyed (DBE) Gene in Devon Rex Cats: What Breeders Should Know

As preservation breeders, we walk the line between upholding breed integrity and needing to be knowledgable when considering exploring genetic variations that emerge in our lines. The Dominant Blue-Eyed (DBE) gene is one of the most hotly debated topics in the Devon Rex world (and frankly in many other breeds as well). Here’s a careful look at what it is, why it’s controversial, and how it can be managed responsibly and ethically.

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What Is the DBE Gene in Cats?

DBE is a dominant gene that produces blue eyes regardless of coat color or pattern. This makes it different from the recessive colorpoint gene, where blue eyes only appear in pointed cats, and also different from the white spotting gene reponsible for blue eyes/odd eyes in solid white or bicolourcats,. In Devon Rex, DBE is relatively rare especially here in North America, but it has drawn attention because of its striking look and the questions it raises for ethical breeding.

Why Is DBE Controversial in Devon Rex Cats?

Part of the controversy comes from the lack of scientific studies. For a long time, the only way to understand DBE was through test matings, the very same way every gene was studied before modern genetic testing became available(in the last 20 or so years). That lack of history and context naturally left breeders cautious. Myself included.

The other major reason is because there are different genes that can cause blue eyes, and some of them have possible health concerns (more on that below). Even today, without a simple test to identify every DBE variant, breeders need to rely on a deep understanding of their lines, transparent records and communication, and thoughtful decision making. DBE is not a novelty project; it requires stewardship from breeders who know exactly what they are working with.

Does DBE Break the CFA Breed Standard?

No. DBE does not contradict the CFA Devon Rex standard. The standard focuses on structure, coat, and overall type, not eye color. DBE only affects eye color.

This is different from something like the longhair gene, which directly violates the standard and disqualifies a cat in the show ring. DBE does not change what makes a Devon Rex a Devon Rex, it simply adds a blue eyed phenotype, an already acceptable eye colour.

What Are the Different Types of DBE?

Researchers have identified multiple DBE variants:

• DBE^RE (Rociri Elvis): Linked to cranial concerns, deafness, and suspected lethality when doubled.

• DBE^CEL (Celestial): Found in Celestial and Topaz lines, not linked to deafness.

• DBE^ALT (Altai): The variant present in Devon Rex. Not associated with health issues when managed responsibly.

• DBE^AGO (Agostino): A newer frameshift mutation in a Maine Coon line, still under study.

For Devon Rex, the typically relevant version is DBE^ALT, not the cranial version DBE^RE. This is a critical distinction and should give breeders reassurance while still urging caution. But in order to know with reasonable certainty that this is the specific variant, it must also be sourced from a breeder with meticulous pedigree information and family history.

What Is Latency (Incomplete Penetrance) in DBE Cats?

With DBE^ALT, breeders must also understand incomplete penetrance. Even though DBE is dominant, it doesn’t always visibly express. A cat can carry DBE^ALT without showing blue eyes, yet still produce blue-eyed kittens.

This “hidden” expression means breeders must keep excellent records, track lineages closely, and communicate transparently with peers. Incomplete penetrance doesn’t make DBE unsafe, but it does demand extrancareful management.

How Should DBE Be Managed in Breeding Programs?

DBE can be managed safely if breeders follow strict precautions:

• Never breed DBE × DBE. This avoids the possibility of bringing accidentally a seperate type of DBE and not knowing which is at play.

• Do not pair DBE with high-white or dominant white cats, as this can increase risks of hearing or vision issues.

• Do not pair when colourpoints could be a result of the pairing, this is to again, ensure you know without a doubt, the mechanism causing blue eyes in an individual cat.

• Track every outcome to build reliable data for the community.

  
  

Can DBE Be Removed From a Breeding Program?

Yes. DBE can be phased out within a few generations if a breeder decides not to continue with it. That flexibility means we don’t need to eliminate high-quality cats from breeding programs just because they carry DBE. It is also the core reason that I myself have chosen to measure the options and decide to take a chance on a single DBE female. Removing cats from the gene pool entirely over one gene, would unnecessarily reduce genetic diversity and discard otherwise valuable type, health, or temperament.

Final Thoughts: A Careful, Measured Approach

DBE has been controversial because of limited study, incomplete penetrance, and the need for extra careful management. But when we separate fact from fear, the picture becomes clearer:

• DBE does not break the CFA standard.

• DBE^ALT is not associated with the cranial issues seen in DBE^RE.

• Provided ethical and cautious breeding practices as outlined are followed, kittens are not harmed.

• The gene can always be bred out if desired.

DBE cannot and should not be about chasing novelty. In the wrong hands and before a DNA test exists, it has the potential to be disastrous. It's therefore about managing a gene with the same responsibility we apply to every trait. But, with the added caveat that it is more complicated to understand than most, so should be handled by those who understand it, their lines and possible ramifications.

With ethics, transparency, and care, DBE can coexist with preservation breeding even if people decide to remove it entirely from their program, without sacrificing genetic diversity in the Devon Rex for generations to come.