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A DNA test for L2-HGA in Staffordshire Bull Terriers.
What is L2-HGA?
DNA test for L2-HGA
Breeds at risk
Breeding policy
Of the utmost importance is the control of hereditary disorders in breeding
programs. Thus, in order to reduce the frequency or eliminate altogether a
genetic defect, the further spread of the mutant gene has to be prevented
in a family or entire breed. When we find an inherited disorder in our
population (in our breed), especially when the frequency of affected animals
is quite high, most of us would want to exclude all animals that carry the
defective allele on the shortest possible term.
That's not always the best thing to do. Eliminating all affected animals
and all carriers from our breeding programs in just one generation might
result in a tremendous reduction of the breed's gene pool, which could cause
an enormous increase of the level of inbreeding. As a consequence problems
with the vitality of the population would increase and we probably would see
outbreaks of other genetic disorders.
Each dog with the defective allele has many good and important genes that
may be worthwhile to preserve in the population. Selection programs should
be carried out slowly and carefully, taking a sufficient number of generations
to prevent overselection. That is where the breeders' organizations should take
their responsibility towards their breeds. With the availability of a DNA test
for disorders like L2-HGA, selection programs can be extended to the
number of generations needed to make sure that no harm is done to the breed's
gene pool.
Carriers can still be bred to clear dogs. On average, 50% of such a litter
will be clear and 50% will be carriers; there will be no affected dogs produced
from such a mating. Pups that will be used for breeding the next generation can
themselves be DNA tested to determine whether they are clear or carrier.
Therefore carriers can be used for breeding without any danger of producing
clinically affected puppies, provided that all breeding animals are tested
and combinations of dogs that could produce affected puppies are avoided.
Testing for L2-HGA
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