WHAT IS A CHARCOAL?
The Charcoal Expression is a pattern effect (not a pattern) where the genes responsible for pattern turning on and off the light and dark pigments affecting the appearance of the pattern.
One of the genes (APb) is a gene only found in the Asian leopard cat is part of the combination that creates the charcoal expression. Despite popular belief, charcoal can express in cats that have the genetic combination of APb/a and APb/APb.
The charcoal looks different from the other non-charcoal Bengals. Charcoal can be seen in all colors and patterns. Some of the most notable characteristics include:
Overall darker markings and background color making it look like a shadow has been cast over the cat
Zorro like mask running over the nose, and connecting over the cheeks, temples and around the eyes
White or near-white goggles around the eyes
A thick stripe running the length of the back referred to as a cape (which may not always be seen in minks, lynx and sepias.
Charcoal is caused by a gene that affect dark color
Charcoal can express in APb/a and APb/APb. cats
Charcoals are characterized by
Our foundation breed, the Asian Leopard Cat, holds a unique gene…. Agouti Prionailurus bengalensis, or APb. This trait did NOT originate from domestic cats. In fact, we can find other examples in nature such as the Iriomote cat, an endangered subspecies of the Asian Leopard Cat found in Japan as well as the partial melanistic jaguar.
It is an agouti gene found on the A allele. The gene was only discovered in the last few years and with the help of UC Davis and Optimal Selection, can now be identified genetically.
APb is NOT codominant; it is incomplete dominant as we understand so far. In regards to other A alleles A dominant over APb which is dominant over “a” in which APb competes with “a” often increases in strength over time.
Many other felid specific variants most likely influence its expression in the domestic cat and it is suggested there are numerous APb genes, that we are in the throes of discovering.
Further, this gene is integral to the charcoal expression. At least one copy needs to be present in order to produce this expression. We have seen it express most notably in APb/a genotyped cats but we are also seeing cats with the genotype APb/APb. Because of “A” dominance over APb we have yet to see charcoal expressed in APb/A genotyped cats.
One study (the only one to date on this topic) published in 2014 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, suggests a basic understanding of the study concluding that because charcoal Bengals are seen in early generation cats, that the charcoal expression comes solely from the APb (ALC agouti variant) and "a" (domestic non-agouti variant) resulting in the APb/a genotype. However, researchers stated that other coloration genes will affect predicted expression of APb including color and tabby pattern thus is not out of the question that we will see charcoal expressed in other genotypes. It is also suggested by genetic researcher Christopher Kaelin PhD, that numerous ALC agouti genes have been introduced that we have yet to discover.
The charcoal expression also is neither a color nor a pattern. Its expression can be seen in every color and pattern known to the Bengal breed. Understanding the difference between a Pattern EFFECT and a Pattern is integral to the charcoal expression.
These two terms Pattern and Pattern Effect are not interchangeable. Pattern is a style of markings that displays in predictable ways. The four tabby patterns are Mackeral tabby, Classic Tabby, Ticked Tabby, and Spotted Tabby which is often considered a variant of Mackeral.
A Pattern effect is how agouti controls light and dark pigments that affect patterns.
At its simplest, a PATTERN is how the markings are displayed on the cat. When agouti alters the way it typically controls light and dark pigment, the results can change the expected pattern resulting in a Pattern Effect.
Let us relate the PATTERN EFFECT to COUNTERSHADING. Countershading is the white underside we see in a variety of animal species which functions as a camouflaging pattern.
Countershading is not only seen in Bengals but the Adelie Penguin, Cavier Gizelle, the Anole Lizard, and many more mammals, sea creatures, and insects.
When parting the hairs on a white countershading pattern, one will find gray at the hair base. When agouti produces dark pigment too early in the hair growth, the gray extends too far up the hair shaft causing the countershading pattern to be gray instead of the expected white. This is an example of how agouti alters the countershading turning it from white to gray, from light to dark.
In Charcoals, we see the pattern effect on the top side of the cat. Agouti has allowed the production of dark pigment for too long resulting in overall darkness, mask and cape. In short, agouti is like a control panel that turns on and off dark and light pigment. For the charcoal cats, agouti has produced dark pigment earlier and longer than that of a non-charcoal cat.
Let’s simplify this further.
Imagine, a child is asked to color a brown Bengal and he has been given one black and one yellow crayon. The child has to combine black and yellow to color a “brown” Bengal. The child who uses more of the black crayon than the yellow crayon will end up coloring a charcoal Bengal. Ultimately the “pattern” on a coloring book cat is the same, the amount of black crayon used in comparison to the yellow crayon alters the appearance of the pattern.
Base Cat with a spotted/rosetted pattern
Same cat, same pattern the black color just appears to ALTER the existing pattern
Same cat, the same pattern
Pattern is how the banding of the hair shaft results in markings.
Pattern Effect is how pigment distribution alters the standard patterns.
APb is integral to producing charcoal
There are various APb genes some yet to be discovered
APb, when combined with domestic felid genes, produce varying effects of color and pattern
APb/a and APb/APb genetyped cats can produce charcoal
Charcoal can be seen in all colors and patterns
Charcoal is a Pattern Effect (NOT a PATTERN) in which the agouti gene influences the light and dark pigments affecting its distribution.
This information is a collaboration of Meghan Waals of Elysian Bengals and Robyn/Jon Paterson of Quality Bengal Kittens
This presentation was put together by Meghan Waals in conjunction with the moderators Steven Corneille and Carlos Lopez. It was presented on May 30th to 70+ TICA judges from around the world to help aid them in understanding charcoal and how to judge them.