DNA or deoxyribonucleic acid is carried in the nucleus of every living cell and contains the genetic material used in the development and functioning of all organisms.
DNA was first discovered in 1869 by Swiss scientist Friedrich Miescher but
it was not until 1953 that James Watson and Francis Crick discovered its actual structure. They discovered that DNA is comprised of two strands known as chromosomes, twisted in a spiral or helix, with cross pieces like
a twisted ladder. In 1962 Watson and Crick received the Nobel Prize for
their work though it was not until 1966 that they managed to crack the genetic code.
Paired chromosomes contain DNA in a double helix structure and contain thousands
of paired genes along their lengths. A gene is a molecular unit
of heredity of a living organism, and they hold the information to build and maintain the cells and pass on genetic traits to the offspring eg eye colour, number of limbs, blood group, hair colour etc.
When the cells of the body duplicate, the DNA also replicates itself, though not always accurately. When errors occur they are known as mutations and these can give rise to either inherited diseases or physical and mental abnormalities.
The advantage of a DNA test for a particular health issue, is that it provides an accurate genetic result rather than the ‘hit and miss’ results of clinical tests. Genetic tests are fantastic tools for breeders to make use of and Collie breeders are now fortunate in having DNA tests for:
caused by a Growth Hormone deficiency, which may be inherited, with affected dogs usually appearing normal at birth, but showing evidence of failure to grow by two to three months of age. The condition affects all breeds and cases have been diagnosed in our Collies — Genetic Testing Laboratories Laboklin & Animal DNA Diagnostics
Degenerative Myelopathy, a non-
the Choroidal Hypoplasia (CH) aspect of Collie Eye Anomaly — Genetic Testing Laboratories Optigen &
Knowing the genetic health status of a given dog or bitch is hugely beneficial for
breeders as it enables us to estimate the
health status of our
puppies as follows:
Clear to clear = 100% clears
Clear to carrier = 50% clears & 50% carriers
Clear to affected = 100% carriers
Carrier to carrier = 25% clears, 50% carriers & 25% affected
Carrier to affected = 50%
carriers & 50% affected
Affected to affected
= 100% affected affected
Laboklin, Optigen & Animal Genetics have official schemes whereby test results are
submitted directly to the Kennel Club if requested on
the order form.
Breeders can also submit copies of test certificates directly to Nick Sutton at the KC.
It is now compulsory
for all dogs to be microchipped.
The Kennel Club is considering making DNA profiling
mandatory, as a means of confirming the parentage of a particular animal.
Breeders can have litters from dual matings without the prior approval of the KC. puppies can be registered providing they have first been DNA profiled to determine their parentage.
The kennel club accepts that a two-
the advantage of producing
two litters in one gestation/whelping, so aiding the expansion of the gene pool more rapidly.