| Well, no one has tried to answer this question, but I will give it a
shot.
Brother to sister, mother to son, father to daughter are all examples
of inbreeding--breeding of closely related individuals.
Line breeding is breeding of cats from one line that may not be that
closely related. Sometimes the differences between line breeding and
inbreeding are not that great.
Outcrossing is breeding individuals that are not related at all. It
can also mean breeding different breeds together.
There isn't really a magic number of times that a line can be inbred
before problems start to show up. Sometimes problems will show up
immediately, in the first inbred generation. Inbreeding can be an
important tool in developing a breeding program. Since most
undesirable genetic problems are recessive in nature, inbreeding would
cause those faults to show themselves in the offspring. Once the
inbreeding has been done, if any genetic faults show themselves the
breeder would then know what they were dealing with and could plan from
there. If no genetic faults showed themselves, then the line would be
considered clear and safe to use for breeding. (there are always
exceptions to this theory--this is just a generalization)
Anytime you select individuals for breeding from a small gene pool, you
are running the risk of weakening the immune system. It is my opinion
that most purebred animals are not as hardy as their garden variety
cousins. I consider this to be a given. It is my goal to change that.
But, I think that it is important for buyers and breeders to know that
purebreds can have a weaker immune system, and they should take the
necessary precautions to protect them from immune system challenges.
Jo
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| re: .1 - absolutely true, and well spoken as well.
However, there is one side-effect that CAN result from "inbreeding" or
"line breeding" (as Jo said, they can often be equivalent)...the animals
produced CAN have certain positive characteristics enhanced or "locked in"
by these breedings. In the case of physical characteristics, this is most
often true, which is why the inbreeding occurs, and is even required to
stabilize a breeds' characteristics when the breed is new. another positive
effect can be increased intelligence. Yes, in spite of the horror stories
about inbreeding, the offspring are often VERY smart -- especially if the
parents are smart to begin with. Why this is true isn't totally understood,
but it is often the case. Therefore, the breeder has the possibility of
breeding an exceptionally beautiful, intelligent member of the species/breed...
if the dangers inherent in the limited gene pool don't manifest.
The challenge of inbreeding and line breeding is to balance these positive
effects while adding the hardiness that comes from an expanded gene pool by
selective out breeding.
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