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A DNA test for Congenital Stationary Night Blindness (CSNB)
What is CSNB?
A DNA test for CSNB
Breeds at risk
Breeding policy
Most important is the control of hereditary disorders in breeding programmes. In
order to reduce the frequency of a genetic defect or eliminate it altogether, the
further spread of the mutant gene has to be prevented. 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 programmes 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 programmes 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 CSNB, selection programmes can be extended to the
number of generations needed to make sure that no harm is done to the breed's
gene pool.
Testing for CSNB
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