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Note: These pages were initially written as weekly lessons for a
Bengal list I was a participant on. They asked me to put
something together because many of the same questions and
misconceptions kept coming up. They were published here so that
they would be continually available for upcoming new breeders.
That was about 4 years ago. Now (February 2005), I'm updating
these pages with new information that has come from the new Robinson
book and from the Feline Genetic Mapping program from UC Davis headed
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will try to present this topic with fun, understandable examples,
diagrams
and whatever else is necessary to make this interesting and fun as well
as educational. Please, please, please ask questions, I
can't
see the questioning look on your faces so you'll have to let me know
that
something needs to be explained a bit differently. Email your
questions and I will answer you individually.
There is a definition page that is being published along with these lessons. The text of each lesson will have the technical words as links to the definition page. That way the person who knows the term doesn't have to stop to read a definition she already understands and the information is handy for the one who doesn't know or needs a refresher. You can print the definition page if you'd like. There is also a symbols page that explains the genetic symbols and which trait is dominant, recessive, or co-dominant. |
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| Genetics
is a science. It is the study of inheritance. In other
words
"why do I look like Dad's Aunt Gertie instead of my own
Mom"?
Genetics is NOT random as some believe. It is a science with
specific rules just like the more common rules of gravity, etc., that
we
are all familiar with. However, until recently
the only way for scientists to determine how a trait was inherited was
by observance of when it showed up and under what circumstances.
In other words, we were (and still are) just exploring this fascinating
science. Now, the Feline Genome is being mapped and already some
tests are available to tell us what traits our cats carry.
However, this is still fairly costly (at about $50 per cat) and it will
not take the place of studying this science if you want to advance your
quality of the cats you produce in you breeding program. It is much more than the inheritance of color, hair length, eye placement, ear size, or even body conformation. It is also the genes that control the lungs, heart, blood, and ALL tissues and functions of all living bodies. The DNA in each cell tells that cell how to be a "team player" and that is what creates the whole person (or plant or animal). It is the inheritance of all biological functions right down to the cell level. (If you think about it, this is about as astounding as anything can be!) Did you know that a heart muscle cell is so specialized that if you separate it from the body, it will continue to beat in the same rhythm of your heart? Somewhere on one of it's chromosomes is a gene that orders this cell to beat! That same gene in a leg muscle cell, for example, is inactive UNLESS you place it in very close proximity (petri dish) with the heart cell. Then, it will modify and begin beating AND the beating will match the exact rhythm of the other heart cell! This is called specialization and is why a graft of skin from your back where there is very little hair can still produce hair if grafted to the top of your head! All of these functions (brain activity, heart, lung, kidney function, etc.) is controlled and regulated by genes located in every cell of our bodies. We are going to be learning about only a very few genes. There are millions that we don't need to be concerned about, for the most part anyway and a few more that we need to learn more about before they will begin to be understood. |
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Of
course, we all know you can do exactly that. A Tom-cat
and
a Queen allowed access to each other will make babies. But, will
they give you the babies you want? And, will these babies be a
step closer or further away from what you are striving for? Will
they be healthy? A
knowledge of genetics is no guarantee of health or of (always) getting
the color you want but it goes a very long way toward these goals.
And, it gives you the knowledge to adjust your breeding program when
surprises turn up. Let's say a newbie breeder gets a great deal on a pair of beautiful tri-color marble Bengals. Now, this breeder would have preferred a spotted pair but this was too good of a deal to pass up. He knows that both of these cats had a spotted parent so he's hoping they carry and he'll get spotted babies. Will he? No, probably not, and that seems so easy now - but, if you'll think back, there was probably a time when you might have been stumped by this question or thought the same as this newbie. Now it seems almost silly. With some other genetic basics under your belt, you'll be able to see the majority of the genetic puzzles presented to you in your quest for better, prettier Bengals - just as easily. In talking to exhibitors and breeders over the last several years, I've come across some very interesting comments and misconceptions. One of the first, was at a show when I asked a Bengal breeder if snows were recessive. The answer was "no, they just pop up once in awhile out of the blue." I kid you not, this was an exact quote and I found out later these folks had been breeding Bengals for several years and dogs for over 20!! This is why we need to have at least a basic understanding of genetic principles and how they apply to our cats. (I don't know if these breeders wanted snows in their program or not, but obviously they didn't know how to encourage or discourage snows from "just popping up" either.) Here's another question to test yourself with: If you cross your brown spotted boy with green eyes with your blue eyed snow (Lynx point) queen, is there a possibility any of your kittens will be snows with the dad's green eyes? Why? Send me your answer. (The answer and why - next lesson.) If you'd like to discuss it or ask questions. I'd be happy to correspond with you. |
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In order to understand some feline genetics, it is a good idea to
understand
where the domestic cat originated and how they got to where they are
today. Then, studying current breeds and understanding ours will
be easier. The "wild cat"
was a short haired tabby similar to our classic tabby that was native
to Africa 4,000 years ago. These cats were encouraged to come out
of the "wild" and hang out around the Pharaoh's granaries to kill the
rats and mice who came there for a free lunch.
Above are Sokokes.
This is probably as close to the "wild" ancestors of our
domestic cats as we'll ever see.
Wahadi's (left) parents come straight from Africa with no influence yet from "man". Densi (right) is out of older stock, bred in Denmark & Italy for some years, yet still very little change from the African stock. These cats are all versions of the classic tabbies though the "design" of the classic varies some from each individual, but all are a form of classic. The pattern is not "clear" as no one has selectively bred for that. <gg> (c)Patsu The classic tabby pattern is often referred to genetically as the "wild type" and is controlled by four genes, the "A" genes that control the agouti (background) of the pattern and whether or not any pattern is visible, the "T" genes that control whether the cat is ticked or not, the Mc genes that determine the type of tabby pattern, and the Sp gene that determine whether the pattern is or isn't broken into spots. In the wild type tabby the genetic make up would have been: AA,tata,mcmc,LL,spsp (short haired classic tabby). All other colors and patterns, body types, hair length (or lack of), straight or curled, heavy boned or fine, all are mutations of the original or wild type pattern. For a further explanation of the above "wild type" genes:
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Agouti vs Ticking (and the basics of dominance) |
