Genetics
Brindle in Dogs: How the Tiger Stripe Pattern Is Made
Brindle creates a striped pattern of eumelanin over phaeomelanin — like a tiger's stripes on a dog. Here's exactly how the kbr allele produces this striking look.
May 15, 2024 · 4 min read
The Genetic Mechanism of Brindle
Brindle is produced by the kbr (brindle) allele at the K locus. Brindle creates irregular streaks of eumelanin (dark pigment) over a phaeomelanin (red/fawn) base coat. For brindle to be expressed, the dog must: (1) carry at least one kbr allele, (2) carry no KB allele (which would mask the pattern), and (3) have at least one phaeomelanin area for the stripes to appear on.
Brindle Combinations and Their Expression
- kbr/kbr: True brindle — strongest stripe expression.
- kbr/ky: Brindle over the phaeomelanin areas; may be lighter brindle.
- KB/kbr: Dog appears solid (KB masks everything) but is a brindle carrier — can produce brindle offspring.
- kbr with Ay (sable): Can produce brindle sable — sable with additional striping over the phaeomelanin areas.
Brindle in French Bulldogs and Other Breeds
Brindle is common in French Bulldogs, Mastiffs, Boxers, Cairn Terriers, and many other breeds. In French Bulldogs, brindle ranges from light 'reverse brindle' (so many stripes that the dog appears mostly dark) to 'tiger brindle' (distinct dark stripes on a lighter background). Brindle is a traditional French Bulldog color accepted by the AKC breed standard — unlike blue, merle, and lilac which are non-standard and associated with health concerns.