English Bulldogs USA, LLC

  Chocolate Bulldogs: The Sweet Side of English Bulldogs

Introduction: Chocolate Bulldogs, also known as Brown Bulldogs, bring a delightful twist to the world of English Bulldogs. These charming canines have a unique coat color that sets them apart. In this article, we'll explore the genetics, characteristics, and details that make Chocolate Bulldogs a special and sweet addition to the bulldog family. There are so many variations of what a Chocolate Bulldog is that it's impossible to capture each one uniqueness. With color modifiers you can have Full Suited Chocolates (no or little white); Chocolate Tri's/Trindles (a Tri with brindling); Chocolate Seals; Chocolate Merles with Tri/Trindle or Merles that are Cyptic (can hardly see it),   Chocolate Harlequin Merle, or Chocolate Tweed Merle; Chocolate Platinums/Fawns; Chocolate Brindle; Chocolate Pied; Chocolate Fawn/Sable. Please get your bulldogs DNA tested to find out exactly what color you have. 

Genetic Makeup: TYRP1 Gene Chocolate Bulldogs owe their distinct color to the TYRP1 gene, a modifier of eumelanin. Unlike the dilution gene in blue-coated dogs, the TYRP1 gene doesn't dilute the pigment but changes its shape. This modification reflects light differently, transforming the black pigment into a rich chocolate hue.

There are two alleles for the TYRP1 gene:

1. B (Dominant): Full base color, does not carry chocolate.
2. b (Recessive): Brown or chocolate color.

A Chocolate Bulldog can have the genotype:

• BB: Does not carry chocolate, full base color.
• Bb: Carries one copy of the chocolate gene.
• bb: Two copies of the chocolate gene, resulting in a full chocolate coat.

OR 

1. BBdd or Bbdd: Blue (non-chocolate, dilute)
2. BBDd or BBDD: Black (non-chocolate, non-dilute)
3. bbdd: Isabella (chocolate, dilute)
4. bbDd or bbDD: Chocolate (chocolate, non-dilute)

Appearance: The chocolate coat of these Bulldogs should be shiny, resembling brown against black objects or in the sunlight. The presence of the seal gene may introduce different undertones to the coat. Interestingly, when the hair is rubbed backward, some Chocolate Bulldogs may reveal a fawn undercoat.

Key features of Chocolate Bulldogs include:

• Nose, Footpads, & Eyeliner: Always chocolate, even in chocolate fawn variations.
• Fawn Undercoat: Present in some individuals when the hair is rubbed backward.

Details: The Sweet Variations While the hair color on Chocolate Bulldogs can vary slightly, the liver-colored nose is a non-negotiable characteristic. The nose, eyeliner, and foot pads should exhibit various shades of brown, ranging from Hershey-type chocolate to a more diluted chocolate, as seen in chocolate fawn/sable variations.

Key points to note:

• Nose Color: The best indicator of a true chocolate; should be liver (brown).
• Effect on Black Pigment: The chocolate gene affects black pigment, turning it into chocolate, including all patterns.
• Eye Color: Usually transforms to amber, yellow, or gold or light brown.
• The nose, eyeliner, and pads should have brown variations. 

The chocolate gene is recessive, requiring two copies to manifest on the dog. When a dog has a full black base and is bb, the entire black coat turns into a rich chocolate color. The combination of a chocolate dog with a blue dog (bb + dd) results in a unique lilac or isabella color.

Check out this great PDF from Animal DNA Diagnostics 

Color Coat Modifiers

The base color of any Bulldogs can be enhanced with Tri points, brindle, seal, and merle, providing a unique aesthetic.

• Tri Points - {at/at} the "at" Allele: Bulldogs carrying two copies of the at allele present a black and tan or tricolored coat. A tricolor dog is black-and-tan with white, and the at allele is always passed on to potential offspring.
• Brindle, Trindle, and Seal {K Allele}: The genes responsible for the brindle pattern are not fully understood. The K gene, specifically Kbr, plays a role in brindle patterns. The agouti gene overrides the brindle gene on the body coat, making it appear solid color. The K gene is visually inspected to determine if it's Kb (Seal) or Kbr (Brindle).
• Merle: This coat color pattern is characterized by splotchy patches of diluted colors. It is governed by a SINE insertion in the Pmel17 or Silver (SILV) gene. Merle only dilutes black pigment, and there are three alleles for merle: M allele, Mc allele, and N allele.
• Dogs with cryptic merle may display minimal merling and can be mistaken as non-merles. The inheritance of merle is genetically unstable for both M and Mc alleles.

Complexity of B Genotype:

• Three sequences to the b genotype: b, b2, or b3.
• Labs may or may not recognize all three sequences.

Coat Color Complexity:

• Coat color genetics is complex, with multiple loci and alleles.
• Ongoing research may lead to updates in our understanding.

Conclusion: A Delectable Addition Chocolate Bulldogs, with their unique genetic makeup and distinct appearance, bring a touch of sweetness to the world of English Bulldogs. The careful consideration of genetics ensures that breeders can predict and produce these delightful chocolate-coated companions. Remember DNA and the understanding of how colors are produces is an ever changing learning process. What is known today could be rewritten tomorrow. 

At English Bulldogs USA, LLC, we take pride in unraveling the genetic mysteries behind our Bulldogs. Each Bulldog is a testament to our meticulous breeding practices and unwavering dedication to preserving the unique qualities of this beloved breed. 

Written with help from Chat GPT. A big thank you to Central PA Wiggle Butts Bulldogs for the use of one of their puppy photos.