WHAT IS A CHARCOAL
WHAT IS A CHARCOAL
In addition to Silvers, Elysian Bengals also specialize in charcoals. The gene responsible for this expression comes from the one and only Asian Leopard Cat, the wild cat that helped to formulate our breed. We are enamored by their unique beauty
A charcoal is a Bengal Cat that has darker expression, "Zorro" mask on their face, white goggles encircling the eyes and a dark wide dorsal stripe or "cape" running down the length of their back.
One theory is that Charcoals can only have a genetic color code of APb/a (Asian Leopard cat agouti + domestic agouti) however given numerous examples not only in presenting cats but research, we propose that Charcoal can present regardless of genotype.
To learn more about our proposal keep reading!
the album below displays examples of some Charcoals we have produced and brought into our program as well as cats that do NOT present as charcoals.
Welcoming the Charcoal Bengal to the Show Hall
Meghan Leah Waals
We propose that Charcoal is a pattern effect defined by the presence of darker expression, mask, and cape as well as near white goggles encircling the eyes. Genotype should be disregarded when determining if a cat is a Charcoal.
We propose the following addition to the TICA standard to have charcoal recognized as its own pattern effect within the Bengal Breed Standard (see below to address other breeds):
Charcoal Tabby: The face should include a mask that is dark in color. It should run over the nose and connect at the cheekbones. In addition, the eyes shall be encircled by near white colored goggles. There should be a broad dark dorsal stripe running the length of the back (preferable but not required in the color point series ONLY).
We are requesting a change to section 71.8 Color and Pattern Variations and section 74.2 Tabby (Torbie) Colors.
Add to section 71.8:
Charcoal Tabby - A pattern effect caused by an agouti variant affecting pigment distribution. It is characterized as an increase in dark pigment wherever pigment is already present on the tabby coat. This creates multiple pattern effects on the coat such as darker ground and marking coloration, a broader dorsal stripe, and/or a noticeably darker coloration along the nose bridge and cheek bones, which are accented by near white goggles encircling the eyes. Charcoal is a tabby pattern effect and not a color. All patterns of the charcoal tabby are possible, as are all basic eumelanistic colors. The charcoal effect is the result of the use of the Asian Leopard Cat (Prionailurus bengalensis) in the development of the Bengal breed.
Add to section 74.2:
Charcoal tabbies are the result of a pattern effect caused by an agouti variant affecting pigment distribution. It is a dominant trait caused by the APb gene. All patterns of Charcoal tabbies are possible as are all basic colors. On patterned tabbies (i.e. mackerel, classic, etc.) the Charcoal effect appears in the ground color and marking coloration.
Charcoal Tabby Color Terminology:
Insert Charcoal before pattern
Brown (Black) Charcoal Spotted/Marble
Seal Charcoal Spotted/Marble Lynx (Tabby) point
Black Silver Charcoal Spotted/Marble tabby
The Agouti Prionailurus bengalensis (APb) also known as the Asian Leopard Cat (ALC) agouti gene is a developing topic in the Bengal breed. While not all Bengals have APb in its genetic code, this gene has the possibility of being inherited and is unique to the Bengal cat. APb is also part of an evolving equation that makes up the charcoal expression.
According to the University of California Davis, Agouti is a gene that is responsible for the presentation of black pigment. When you look at the results of a color test you first will see the A allele (an allele being a trait that is contributed to the offspring, one from each parent). "A" is responsible for a banded hair shaft that presents more of a tabby pattern whereas "a" plays a role in masking pattern. The most extreme of this is in a solid cat whose genetic code is a/a (1). The Bengal cat was developed from breeding an ALC to a domestic cat. Both “A” and “a” have an origin with the domestic cat however APb, comes strictly from the ALC.
To date, only one study has been published that focuses on APb in the ALC and domestic Bengal Cat. Conclusions from this study suggest that because charcoal Bengals are seen in early generation cats, that the charcoal expression comes from the APb (ALC agouti variant) and "a" (domestic non-agouti variant) resulting in the APb/a genotype (2). Therefore, it seems the general consensus is that APb/a genotyped cats qualify genetically as charcoals versus other genotypes.
We propose that charcoal is a pattern effect and that through current and ongoing research we have and will come to understand there is more to this expression than a genotype.
The study mentioned above entitled Who's behind that mask an` cape? The Asian leopard cat's Agouti (ASIP) allele likely affects coat colour phenotype in the Bengal cat breed, concludes that the charcoal expression (defined by the researchers as "An unusual pelage [fur] type involving a darker face ‘mask' and a dark dorsal stripe, commonly referred to as a ‘cape'….") is a genotype denoted by the APb/a color code sequence.
While the study identified that the pairing of the ALC agouti variant and domestic non-agouti variant are responsible for the charcoal expression due to the prevalence of charcoal expressed cats in early generations, it did not identify the causation for other genotyped cats presenting as charcoal.
As mentioned in the study "Inhibitor (I) Siamese (cs) and Burmese points (cb), brown variants (b, bl) and dilution (d) … these colouration genes often confound proper phenotyping." And "Other wild felid-specific variants will likely affect tabby patterning as well as other aspects of colouration and morphological variation." In other words, other genes alter the presentation of APb affecting color and pattern making it not unreasonable that other genotypes can still express as a charcoal.
This again suggests that there is far more at play in the expression of charcoal than simply an APb/a genotype. After all the study does conclude "The allelic relationships of ASIPAPbe with ASIP-A and ASIP-a are not fully understood, and more systematic studies are needed to determine the mode of inheritance for charcoal." (2)
Dr. Christopher Kaelin is currently studying Asian Leopard Cat ancestry in the Bengal breed. The as yet to be published research suggests that the ALC ASIP allele has been introduced into the Bengal breed multiple times, by different ALCs. Independent introductions of an ALC ASIP allele have similar effects on coat color. For example, a common agouti variant is A2. It is an ALC agouti variant that doesn't cause the charcoal phenotype. We are also aware that there are different agouti genes in different leopard cats with the same expression.
The expression of charcoal can be compared to the difference between brown versus silver cats. Simply apply the inhibitor gene and your brown now no longer is brown in color, most or all the warm tones are inhibited, and you now have a silver cat. Without this modification, you have a warm-toned brown cat. Silver isn't technically a color it's a modifier (3). The APb gene interacts with various other genes to change the color and pattern of the base cat.
At this time, we can safely say that Charcoal isn't really a pattern simply because it exists in all existing patterns only with slight changes. We know now APb, is a specific ALC agouti gene and its role plays a part in the charcoal phenotype. Our understanding is that the agouti signaling protein (ASIP aka "agouti gene") is responsible for the regulation and distribution of eumelanin pigment and banding on the hair shaft. The ALC's ASIP messes with the normal amount of melanin production and causes a drastic increase in the amount of pigment expressed. In browns, the rosettes often become so black, that it's difficult to see the outer lining of the rosette giving them solid spots instead, ground color also changes from the normal shades of brown to varying metallic shades, pigment on the face also becomes significantly darker giving the cat a "mask" and so forth.
Contrary to our initial thoughts, the charcoal is NOT caused by incomplete dominance between the ALC agouti and domestic non-agouti. The charcoal phenotype has been proven to express in both homozygous ALC agouti cats (Apb/Apb) as well as heterozygous Apb cats (Apb/a). Ultimately, we may be able to completely eliminate the non-agouti from charcoal programs as the phenotype continues to progress.
A > Apb > a
Apb/Apb = Charcoal
Apb/a = Charcoal
There is no standard for the charcoal expression. While a single study suggests charcoal is the result of the cross of the Asian Leopard Cats and domestic cats producing APb/a, studies don't indicate that other genotypes involving APb are not a charcoal.
This clarification, definition, and standard are extremely important for the show hall and Bengal Breeders alike, especially as this non-standard and emerging color, becomes more commonplace and popular.
How should TICA define and categorize the charcoal?
Back in 2009 and around the time where we originally hypothesized that the charcoal was a result of the Asian Leopard Cat’s ASIP, other breeders working in the color reached out to several geneticists including Leslie Lyons, Brian Davis and Solveig Pflueger. After providing the data we had already collected, Dr Pflueger gave them the recommendation to approach the charcoal as a “pattern that modifies color”, a pattern effect and gave the comparison to the grizzled tabby Chausie.
The Grizzled Tabby and the Charcoal actually have a surprising amount of similarities. Not only are they agouti variants inherited from their respective wildcat ancestors, but they also cause a dramatic increase in eumelanin pigment and are possible in all eumelanistic colors and patterns. Following Dr Pflueger’s advice, it makes a lot of sense to approach the two phenotypes in the same manner.
But there’s also another reason why approaching the charcoal as a pattern effect is the best approach: Simplicity.
If we take a moment to review TICA’s color coding chart.
-If the charcoal is approached as a color modifier, it would require the addition of eight new codes and add roughly seventy new color descriptions to the UCD.
-If the charcoal is approached as a pattern, it would require the use of eight new codes as it overlaps the existing pattern and possibly requires the addition of eight new pattern descriptions.
-If the charcoal is approached as a tabby pattern effect, it would require the addition of two codes (charcoal & charcoal torbie) and a single description to the UCD.
We are requesting for breed section poll to be conducted on the fall 2019 ballot.
Support from the membership and Bengal community would be greatly appreciated as this call of action sees the light of day.
Please feel free to join our Facebook Group Charcoals for TICA
Who's behind that mask an` cape? The Asian Welcoming Charcoal
leopard cat's Agouti (ASIP) allele likely affects to the Show Hall
coat colour phenotype in the Bengal cat breed