A-Kerr's Bengal cats  established 1989

Patterns of Understanding

In the latest edition of Robinson’s Genetics for Cat Breeders and Veterinarians,  a new tabby pattern hypothesis is presented. .  This hypothesis goes a long way in explaining the hard to explain Bengal cat patterns.  Dr. Heather Lorimer, Assistant Professor of Genetics at Youngstown State University (and a member of the TICA Genetics Committee) proposed the following hypothesis after a litter of kittens produced: ticked (like an Abyssinian), mackerel and classic kittens, impossible with a single locus theory.  While the three loci hypothesis awaits peer review, it comes closest to explaining the patterns we see on the Bengal cat and explains impossible genetic happenings. 

Quoted from Robinson’s, page 39:

However, recent breeding studies (Lorimer, 1997) have revealed that at least three gene loci are responsible for tabby pattern in the cat:

The dynamic of this change from one gene locus to three gene loci makes the most sense when detailed out.  For the purposes of this article excerpted from a booklet I am working on, I use a standardized form of an Asian leopard cat that was rendered by Alan Brown from Lisa Arvay’s Asian leopard cat Ritzi.   So the “type” is consistent, the changes you see are strictly pattern related.

Taking the locus order given in Robinson’s:

·       “The first determining if the cat is ticked tabby or not (T^a versus t^a ).

We need to understand the term “ticked tabby.”  A ticked tabby is one in which pattern is not revealed.  Two breeds that emphasize ticking are Abyssinian and Singapura.    The “ticking” is agouti banding selected to be extreme in contrast on the hair shaft… thus a single hair has obvious bands of color that vary from the tip to the base.

Dr. Lorimer explains on her website: http://cc.ysu.edu/~helorime/TabPat.html

“… the ticked gene may break the pattern down even more, producing the even gradient of ticking of the ticked tabby.  In the case of the ticked tabby, cats heterozygous for the ticked allele have residual striping on the legs and tail that is substantially reduced or eliminated in the homozygous ticked cat.”

Since T^a (ticking) is dominant to t^a (non-ticked) in order for pattern to be revealed the cat must be homozygous t^a t^a .

Taking the next part of the hypothesis presented:

·       “The second determining mackerel versus blotched/classic tabby pattern (provisionally Mc versus mc).”     

Brings us to pattern flow. 

Mackerel tabbies: have vertical striping. Mackerel pattern is vertical in flow.

Can be McMc or Mcmc   

Classic or blotched:  mcmc

Classic or blotched can be broken into three basic quadrants: front vertical, middle circular, back spotted. (this observation borrowed freely from Lisa Arvay)

But from the Asian leopard cat we have a horizontal or diagonal pattern flow…. 

Is this a separate locus? 

Or is it a different flow at the Mc locus, such as mz? 

Or is it a polygenic trait influencing genes/minor genes? 

While one can not say for certain, selection for horizontal increases the tendency for horizontal giving the Bengal cat more and more unique patterns.        

At this step of pattern flow or direction, the lines of the pattern are not interrupted.  When Bengal cat breeders speak of marble, they are looking at a pattern with little or no pattern interruption, thus the marble is like lines of uninterrupted or unbroken (not spotted) pattern.

Taking the presentation of the loci again from Robinson’s:

·       “A third determining spotted pattern versus non-spotted (provisionally S_p versus s_p).”

Again, from Dr. Lorimer’s website: “the spotted gene can break the pattern into spots.”

Spotted (interrupted) / non-spotted (non-interrupted)

The locus for spotting, is tentatively named Sp (spotted)  s_p  (non-spotted)  

I find thinking in terms of pattern interruption, I can visualize this better.  Especially when looking at the Bengal cat patterns we are getting. Think INTERRUPTION of the pattern and flow of patterns.

Mackerel, spotted 

Broken classic, or spotted classic (seen also in the Ocicat)

Now it gets interesting…..

It is interesting to look at the pattern of your cat… I have taken thousands of photos of cats over the years, and really observe pattern, flow, and interruption.  I am amazed at what we are now seeing in the Bengal cat, many of the patterns are so uniquely Bengal cat… not from the non-domestic or the domestic flow… just interruption at different places creating a mix that will evolve. 

I look forward to what the next litter will provide visually…  I guess that explains why… one breeds.   So, take some still photos… take a look at the pattern, play connect the dots and have fun!   Visualize the possibilities.

I want to thank Dr. Lorimer for allowing me so many times to bend her ear!

Libbie Kerr

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  installed 3/9/08

libbiekerr@akerrsbengals.com

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