Genetics at a glance
| Genotype | d/d with both b/b and co/co in combination |
|---|---|
| Loci involved | D locus dilution; B locus chocolate; Co locus cocoa |
| Typical UK price | £8,000 – £18,000 |
| Kennel Club | Outside the breed standard |
New shade isabella is a commercial term rather than a formal genetic classification. It describes a dog that is diluted and carries both the B locus chocolate allele and the Co locus cocoa allele, producing a lighter and warmer tone than conventional lilac.
Three recessives deep
The reason this matters is arithmetic. Producing a dog homozygous for three separate recessives requires both parents to carry all three. The pool of dogs meeting that description is small, and it is selected on colour genetics rather than on respiratory function, spinal conformation or temperament.
The predictable consequence is elevated inbreeding coefficients and a breeding population where structural health has been, at best, a secondary consideration. That is the risk being bought, and it is considerably more significant than the coat colour itself.
Due diligence at this price point
At £8,000 to £18,000, there is no excuse for incomplete documentation. Ask for: Respiratory Function Grading certificates for both parents, a full multi-panel DNA test, patella grades, hip scores, and the coefficient of inbreeding for the mating. A breeder operating at this level who cannot produce these has told you where their priorities sit.
Health and cost considerations for this colour:
- Requires stacking three recessive genes, implying a very narrow breeding pool
- Carries dilution and its associated coat risk
- Not Kennel Club recognised
Buying at a colour premium? Get a written insurance quote for the specific dog before you pay a deposit — several UK insurers now load or exclude diluted coats. Our lifetime cost calculator applies the colour loading so you can see the difference over the dog's life.
What we would actually buy
Confirms dilution and cocoa status, and screens for degenerative myelopathy via SOD1 among other conditions. Useful if you are buying at a colour premium and want to verify what you actually bought.
Best for:Verifying a rare-colour purchase, or screening before breeding
Check current priceLifetime cover with per-condition limits that hold up against a single IVDD surgical episode. Compare the per-condition limit rather than the headline annual figure.
Best for:Owners insuring from the day of collection
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Common questions
What is a new shade isabella French Bulldog?
A marketing term for a dog carrying dilution alongside both the chocolate and cocoa brown genes, giving a paler, warmer coat than standard lilac. It is not a formal genetic or kennel club classification.
Why are new shade isabellas so expensive?
Because producing one requires both parents to carry three specific recessive genes, which restricts breeding to a small pool of dogs selected primarily on colour. The price reflects the difficulty of the genetic combination rather than any quality of the dog.
Related reading
Colour genetics summarised for buyers. If you are planning a mating, DNA test both parents through an accredited laboratory rather than relying on appearance.