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The following is a good explanation, by Beth Ladd, of the gene that caused the folded ears
and a real life example:
First of all, I'll say I do NOT know everything about genetics! Never said
that, and I don't believe it. However, I have quite a bit of background in
the subject. So with that said, I know that incomplete dominants are
difficult to understand in expression. Let's look at the scenario and some
numbers--that might help:
Michelle had a kitten that folded for a short time then completely
straightened, making that kitten a GENOTYPIC (the *genetic* properties of an
organism) fold, but a PHENOTYPIC (the *visible* properties of an organism)
straight ear. Michelle bred this visibly straight eared cat to another
straight eared cat, with curiosity concerning whether any of the kits would
fold. There were 3 kittens born to this pairing. That's the background of
the situation.
Now, if you even remotely understand the concept of the incomplete dominant
gene, which is the definition of the folding gene mutation, then you will
understand that an incomplete dominant must be VISIBLE to be transmitted
FULLY (meaning show quality or even remotely show quality) to progeny. The
gene or an allele of the gene MAY be present in any given cat, but if it is
not visible the chances of that allele being transmitted to progeny
decreases substantially. But as with any uncertainty in science, there is a
slight possibility that one or perhaps all 3 of the kittens born in
Michelle's litter might receive that allele. But we need to look at some
numbers.
So, let's run the numbers. I'll not get into the actual statistical
equations, but the fact is that there is a 98.79 percent chance that the
three kittens in Michelle's straight x straight litter will be straight ears.
That leaves only a little more than 1 percent chance that any will fold. It
*IS* possible; however, the sad truth is that NONE of these kittens will get
a FULL expression of the gene to fold--the parent 'fold' in the pairing
didn't have it (strong enough to remain folded), so it seems reasonable that
the progeny will have even LESS of the gene. Make sense? So one or even TWO
might fold slightly, but then will likely straighten completely. The most
important number is this: the chance of a fully folded kitten is less than
.0001 percent.
Genetics is a young field of scientific study and there's a long way to go
to complete understanding, but based on what is known concerning incomplete
dominants, those are the numbers. So while I hope, for Michelle's sake, that
what we know about science can sometimes be wrong and one of these kittens
will fold for her, I do fear that these babies will be straight. Either
way, it's very safe to say that none will be show quality or even breeder
quality (folded).
So the real point here is this--when you are breeding any animal, breed the
BEST of the breed. We all have the same goal, and that is to IMPROVE the
breed. So it should be everyone's goal to breed only the best to produce the
very best kittens we can FOR THE BREED. Straightears are simply lovely
kitties, but for the BREED and for the sake of BREEDING and our rights as
BREEDERS, we need to be responsible and work for the betterment of the
breed. It's fun to wonder about the expression of genes, but having kittens'
for that reason should not be the goal for any breeder. This was not the
case for Michelle--she had a girl that desperately needed to be bred. But I
urge everyone who is breeding, or thinking of breeding Folds, consider that
this is a MUTATION you are working with. Treat it with kid gloves, treat it
with respect--for the CATS' sakes, if nothing else.
Hope that helps with a little more understanding of the incomplete dominant
gene.
*Authored by Beth Ladd |
