Linebreeding is similar to breeding like to like only instead of collecting physical similarities, you are collecting
the genes of a particular dog.
Not exact matches
It's this diversity
of looks that make man's best friend the perfect laboratory for connecting sets
of genes to
particular traits and understanding the molecular mechanisms that govern variation in
dogs as well as humans and other mammals.
If there is a recessive
gene for an inherited disease, such as hip dysplasia, a pup born
of related
dogs has an increased chance
of having that
particular problem.
Even though pet
dogs of these breeds rarely fulfill their original purposes these days, individuals still carry their ancestors» DNA in their
genes, which means that members
of a
particular breed might be predisposed to certain types
of aggression.
Genetic testing
of blood samples is available to identify whether a
particular dog carries the
gene for PRA.
It has recently been determined that some herding breeds
of dogs have a single mutation in a
gene coding for a
particular protein (P - glycoprotein) that will drastically affect the absorption, distribution, metabolism, and excretion
of a variety
of medications used in veterinary medicine.
There is a strong genetic influence here, and it depends on the
particular set
of genes that the
dog will inherit from its parents.
If, at some point in a breed's history, a
particular sire or line
of dogs becomes predominant, inherited problems may start to arise seemingly out
of nowhere simply because attempts to concentrate the desirable
genes of select individuals can inadvertently bring together whatever undesirable
genes are present.
Dogs with DM have two copies
of a
particular version
of a
gene called SOD1.
The degree
of risk varies in
genes like this, but with this
particular mutation it is very high: A
dog with it is 17 times more likely to get cataracts than one that doesn't have it.
Having two copies
of a
particular gene mutation will prevent a
dog from absorbing Vitamin B12, or cobalamin.
The
genes encoding these characteristics become more homogenous or similar between
dogs of a
particular breed or line.
That is, although there may be dozens
of genes contributing to
particular cancer susceptibilities in
dogs as a whole, within any single breed there are likely to be only one or two.
While most breeds fair perfectly well with these
particular types
of drugs,
dogs that carry the MDR1
gene may die as the result
of exposure to these substances.