Dominant Blue Eyes (DBE): Genealogy and Pedigree Analysis

Assigning specific Dominant Blue Eyes (DBE) variants to cats solely on the basis of photographs, visible phenotypes or pedigree interpretations, without supporting genetic evidence, is scientifically unjustified and potentially misleading.

DBE Genealogy: Why a Pedigree Is Not Genetic Proof

The Problem with Unsupported Genotype Assignments

We have personally witnessed and documented instances of specific DBE variants being assigned to cats based on photographs alone, including within private breeder groups and closed channels on platforms. We have also documented inaccuracies in published pedigree analyses and genealogical reconstructions, including incorrect pedigree names, inconsistent phenotypic descriptions and misrepresentations of registered coat-colour classifications.

The concern is not the discussion of possible genetic explanations, but the presentation of unverified assumptions as established genotypes and the use of inaccurate genealogical or phenotypic information to support conclusions about genetic inheritance, particularly when such conclusions may influence breeding decisions.

Different genetic mechanisms can produce similar appearances, while some genetically positive cats may not display the characteristic phenotype at all. Neither photographs nor pedigree records can establish a cat’s complete genotype (Abitbol et al., 2024; Abitbol et al., 2025).

Understanding the Genetics Behind Blue Eyes, Odd Eyes and White Pigmentation

Dominant White (W)

Dominant white is associated with the KIT gene and produces an entirely white coat by masking the cat’s underlying pigmentation (David et al., 2014).

Cats carrying dominant white may have blue eyes, odd eyes or non-blue eyes. Dominant white is also associated with an increased risk of congenital sensorineural deafness (David et al., 2014).

A dominant white cat may carry other pigmentation-related variants whose visible effects are concealed by its white coat. Consequently, an entirely white cat with blue eyes cannot be assumed to carry, or not carry, a particular DBE variant based on appearance alone.

White Spotting (ws)

KIT-associated white spotting produces areas of white pigmentation ranging from small markings to extensive patterns like bicolour, harlequin or van (David et al., 2014).

Blue eyes and odd eyes may also occur in cats with white spotting. However, neither the amount nor the distribution of white can reliably establish which genetic variants are present (David et al., 2014; Rudd Garces et al., 2024).

Dominant Blue Eyes (DBE)

Dominant Blue Eyes is not a single genetic variant.

Six distinct PAX3-associated variants have been identified and described in scientific research: DBE-CEL, DBE-ALT, DBE-RE, DBE-AGO, DBE-NAD and DBE-MARU. Other DBE-associated genetic mechanisms remain unresolved or insufficiently characterised (Abitbol et al., 2024; Rudd Garces et al., 2024; Abitbol et al., 2025; Abitbol et al., 2026).

Several DBE lineages show incomplete penetrance or variable expression. In practical terms, this means that some genetically positive cats may have no blue eyes, odd eyes or characteristic white markings, yet still transmit the variant to their offspring (Abitbol et al., 2024; Abitbol et al., 2025).

These characteristics have not been demonstrated to the same extent for every identified variant, and their health implications may differ (Rudd Garces et al., 2024; Abitbol et al., 2025; Abitbol et al., 2026).

When Pigmentation Variants Occur Together

Different pigmentation-related variants can coexist in the same cat, making interpretation from appearance particularly unreliable (Rudd Garces et al., 2024; Abitbol et al., 2025).

Dominant White and White Spotting

Dominant white and white spotting are associated with different alleles at the KIT locus (David et al., 2014).

In a simplified inheritance model, W represents dominant white, ws represents white spotting and w represents the allele without either effect. Possible combinations include W/W, W/w, W/ws, ws/ws, ws/w and w/w.

A cat with the W/W, W/ws or W/w combination may appear entirely white because dominant white masks the underlying spotting pattern. This simplified notation does not encompass every molecular variation affecting KIT (David et al., 2014).

Dominant White, White Spotting and DBE

A cat carrying dominant white or white spotting may also have a DBE-associated variant. A dominant white coat can conceal underlying pigmentation patterns, while blue or odd eyes cannot establish which genetic mechanism contributed to the eye colour (David et al., 2014; Rudd Garces et al., 2024).

Similarly, cats with white spotting may carry DBE, and the effects of these variants may overlap and increase the amount of white (Rudd Garces et al., 2024; Abitbol et al., 2025).

Multiple DBE Variants

The genetic possibilities are not limited to cats carrying a single copy of one DBE variant.

Depending on the variants involved, cats may carry two copies of the same variant or different DBE-associated variants. Where different variants affect the same gene, compound heterozygosity may also be relevant (Abitbol et al., 2024).

Some DBE-associated phenotypes include extensive white markings resembling harlequin or van patterns, or an entirely white appearance (Abitbol et al., 2024; Abitbol et al., 2025).

Not every theoretical combination has been documented or studied, and its effects on pigmentation, development or health cannot be predicted simply from the appearance of the parents (Abitbol et al., 2024; Rudd Garces et al., 2024; Abitbol et al., 2026).

These examples illustrate why two cats with similar phenotypes may have substantially different genetic backgrounds.

Why Pedigrees Cannot Establish Historical Genotypes

Pedigrees provide valuable information about ancestry, registered colours (if recorded correctly) and family relationships, but they do not provide a complete genetic record.

Most historical ancestors were never tested for DBE. Their registered colours and EMS classifications may also be incomplete, inconsistent or inaccurate.

A historical cat may have carried and transmitted a DBE variant without displaying blue eyes or other recognisable features. Conversely, blue eyes or odd eyes may have resulted from a different genetic mechanism (Abitbol et al., 2024; Abitbol et al., 2025).

Different DBE variants may enter the same pedigree through separate ancestral lines, as demonstrated by the coexistence of DBE-CEL and DBE-ALT in descendants of the Roxi and Seymour lineages (Abitbol et al., 2024). Genealogical records alone cannot establish which untested historical ancestors carried or transmitted a particular variant.

This creates an important distinction that is often overlooked.

The presence of an ancestor associated with a particular DBE variant does not prove that a descendant inherited it. Equally, the absence of that ancestor or a known connection to the lineage does not establish that the descendant is genetically negative.

A breeder who assumes that a cat cannot carry DBE simply because a particular historical cat does not appear in its pedigree may be relying on an incorrect genetic conclusion.

Even when a living descendant has a laboratory-confirmed DBE variant, its pedigree cannot establish which untested ancestor introduced it. Alternative inheritance pathways, including the involvement of other DBE variants, may remain possible (Abitbol et al., 2024).

Why Accuracy in Genealogical Research Matters

The reliability of genealogical interpretations depends on the accuracy of the underlying records. Describing a cat registered under EMS 09 (a small amount of white) as a bicolour (EMS 03) is not a minor terminological error. These classifications represent different proportions of white pigmentation, and confusing them demonstrates a lack of accuracy and due care in the presentation of phenotypic data.

This distinction is particularly relevant to DBE genealogy. White pigmentation may result from PAX3-associated DBE variants, KIT-associated white spotting, or their coexistence. Published research has documented cats carrying both genetic mechanisms, with overlapping pigmentation phenotypes (Rudd Garces et al., 2024; Abitbol et al., 2025). Misrepresenting the extent of white pigmentation can therefore distort the assumptions used to reconstruct possible inheritance pathways.

Inaccurate registered names, inconsistent phenotypic classifications and unsupported genotype assignments undermine the credibility of genealogical research. A detailed pedigree cannot compensate for unreliable source data or genetic conclusions drawn without molecular evidence.

A proposed ancestral origin may be a legitimate hypothesis, but presenting it as an established genetic finding without appropriate evidence is scientifically unjustified.

Implications for Breeding Programmes

Incorrect assumptions about DBE status can have serious consequences for breeding decisions. A phenotypically normal cat may carry and transmit certain DBE variants. If breeding decisions are based on appearance or an assumed absence of a particular ancestral line, genetically positive cats may remain unidentified (Abitbol et al., 2024; Abitbol et al., 2025).

This creates the possibility of unintentionally combining two copies of the same DBE variant or different DBE-associated variants. The consequences are not fully understood and may vary depending on the variants involved, including potential health risks (Abitbol et al., 2024; Rudd Garces et al., 2024; Abitbol et al., 2026).

Appropriate genetic testing is therefore important, particularly for cats from DBE-associated or genetically uncertain lines.

However, a negative result only excludes the specific variants examined and cannot rule out variants that remain unidentified or are not included in the test (Abitbol et al., 2024; Abitbol et al., 2026).

Phenotypic observations and pedigree analysis can support genetic hypotheses, but they cannot replace molecular evidence when establishing a cat’s DBE status or making informed breeding decisions.

References

Abitbol, M., Dufaure de Citres, C., Rudd Garces, G., Lühken, G., Lyons, L. A., & Gache, V. (2024). Different Founding Effects Underlie Dominant Blue Eyes (DBE) in the Domestic Cat. Animals, 14(13), 1845.

https://doi.org/10.3390/ani14131845

Rudd Garces, G., Farke, D., Schmidt, M. J., Letko, A., Schirl, K., Abitbol, M., Leeb, T., Lyons, L. A., & Lühken, G. (2024). PAX3 haploinsufficiency in Maine Coon cats with dominant blue eyes and hearing loss resembling the human Waardenburg syndrome. G3: Genes, Genomes, Genetics, 14(9), jkae131.

https://doi.org/10.1093/g3journal/jkae131

Abitbol, M., Cloquell, A., Kaczmarska, A., Holmes, K., Lühken, G., & Macaulay, K. (2025). Dominant blue eyes in Maine Coon cats: New PAX3 variant and updated phenotypic data. Animal Genetics, 56(3), e70020.

https://doi.org/10.1111/age.70020

Abitbol, M., Eiselé, T., & Lipovenko, E. (2026). Additional PAX3 Variants for Dominant Blue Eyes in Cats. Animal Genetics, 57(5), e70199.

https://doi.org/10.1002/age.70199

David, V. A., Menotti-Raymond, M., Wallace, A. C., et al. (2014). Endogenous Retrovirus Insertion in the KIT Oncogene Determines White and White Spotting in Domestic Cats. G3: Genes, Genomes, Genetics, 4(10), 1881–1891.

https://doi.org/10.1534/g3.114.013425

Published on 23 October 2026