Ok so where did genetics all begin, it had to start somewhere and Mendel, the first person to trace the characteristics of successive generations of a living thing, was not a world-renowned scientist of his day. Rather, he was an Augustinian monk who taught natural science to high school students. He was the second child of Anton and Rosine Mendel, farmers in Brunn, Moravia.
Medical problems can turn “Puppy Love” into “Buyer’s Hell! But medical problems can be avoided with DNA and other testing. Many breeders are very confused as to what DNA screening /profiling is and more importantly readily available to them from a variety of resources.
Many think that only the KC can screen /test and only the tests they perform are actually valid, that is simply untrue, the KC run many schemes in conjunction with different labs across the UK, they work closely with the BVA and a variety of other genetic testing organisations such as The Animal Health Trust and Optigen who are presently looking
for owners to contact them if they have a canine with PRA and cataracts.
Presently the KC are encouraging DNA Profiling , this is simply an I D Scheme , and should not be confused with DNA testing for specific diseases within the canine world. It is likely when your breeder comments that they DNA their dogs that they are just profiled .Some breed clubs members are reluctant to have their dogs genetically tested as this can have an effect on any breeding programme currently being used. Short sighted yes of course, but that covers a variety of issues within the canine world.
It is clear that genetic disease within any breed can be started with just 1 champion dog that was not tested, it can and does cause havoc in any breed, there is no breed in the UK that remains totally free from genetic disease, that is simply due to the whole semantics of the science involved.
These tests are just not ready yet.
DNA profiling simply identifies parentage , whereas DNA screening or testing, identifies the animals who are affected with the disease, (affecteds) the animals who have the defective gene (carriers) and the animals who do not have the affected gene (clears) .
A concerted effort is required by everyone involved with purebred dogs if genetic diseases are to be eliminated. Science is making progress, but the time and expense required for the research point toward this being a long term solution. In the short term, the situation must be addressed using the tools at hand.
Open registries for purebred dogs, administered by their respective breed clubs or independent registry organizations,
appear to be the easiest and fastest way to a short term solution.
Canine Profiling (Genotyping) is used to establish a secure, permanent ID for your canine in case it is lost or stolen. Using the same technology we use to establish parentage among canine families, the unique set of allele sizes for the dog are tested and recorded.Simply DNA stand for ‘deoxyribonucleic acid’, found in the cells of all living things, including the canine body.
The DNA is a very long molecule and is found in the nucleus of cells.Canine sample collection is quick, easy and painless. Anyone can collect a sample using a buccal swab for collecting cheek cells.
The DNA molecule actually consists of two strands twisted about each other in the shape of a spiral staircase (double helix). The building blocks of the strands are referred to as bases. There are four different types of bases
in the DNA molecule and it is the sequence of these that determines our dogs inheritable characteristics. The bases from each strand bind to each other, holding the molecule together as in the stairs on a spiral staircase.
As each type of base will only bind with another specific type, the two strands are said to be ‘complementary’. Two bases binding together are referred to as a base pair (bp).
Canine Profiling (Genotyping) is used to establish a secure, permanent ID for your canine in case it is lost or stolen.
If we consider DNA screening with the successful mapping of the canine genome, DNA screening tests are now starting to help breeders eliminate certain diseases which can be linked to individual genes.
By submitting a blood sample,or even a cheek swab owners and breeders are able to find out if their dog carries a defective gene, even if they do not express the symptoms of the disease, and thus
avoid using this dog in a breeding programme.
This is particularly helpful with diseases where the dogs may not exhibit symptoms until later in life and the disease may not be easily detected through normal health screening tests.
Dr. Herman Hazewinkel in The Netherlands is studying patella luxation in dogs. Although his study is of Flatcoated Retrievers, the data can be transferred to other breeds now that the canine genome is mapped. His goal is to develop a DNA-screening test for patellar luxation, which would be of great value to m\ny toy breeds which appear to have a predeliction to this condition.
Presently DNA technology complements eye examinations but cannot totally replace physical examination yet. So owners are encouraged to still ID their dogs using microchip and Tattoo and attend
yearly eye tests peformed by registered opthalmic vets, I have heard of breeders stating that their own vets just take a quick look at 7 weeks to see if the pups are okay.
Optigen which has had its patent secured in Europe is asking for volunteers,Any purebred dog that has been examined by a board certified veterinary ophthalmologist (ACVO, ECVO) and that has been diagnosed with PRA is eligible for review for possible inclusion in the Free Testing program. Status of “PRA suspicious” or “atypical PRA” does not qualify.
So in short DNA profling schemes run by the KC are a great starting point for all breeds, they positively ID parents and progeny what they dont do is screen for disease, that is specifically covered for some breeds through testing and is being updated regularly.All breeders must learn the differences, as the information they pass to new owners must be accurate and not mislead or misinform.
It simply would not be feasible for individual breeders without specific genetic training to compare results from profiling for any future use within an individual breeding programme,The problem with all the mass media coverage and subsequent word-of-mouth between people who suddenly find themselves (or their dogs) personally connected with the subject,
is that misinformation and misunderstandings abound.
Hopefully we have managed to dispel some of the misunderstandings which have surfaced among breeders. The Profile test searches out a set of preselected “markers,” short segments of DNA. The entire set of markers makes up only a very tiny portion of the dog’s total DNA– less than one hundredth of a percent.
It provides no information at all about other DNA,including that cataract gene that might or might not have been passed down three generations .You are constantly bombarded by snippets of information by some breeders who like to Empire Build, they are better than you brigade,they can be overheard saying “well the most wonderful thing about all this DNA testing that the clubs are doing is how it will someday end genetic disease! “Unfortunately, it won’t. The current testing programs are for paternity only.
The markers used aren’t even genes. (Not every part of the DNA is.)
No record is being made of anything but the markers, so they can’t be used in the search for disease genes. All the time we hear about “false positive” and “false negative” lab tests.
Some of this DNA stuff has to be wrong sometimes, too. False readings are very unlikely. Paternity tests use multiple markers to minimize the possibility of error or mutation skewing the result.
The possibility that the test result would be incorrect are too minuscule to cause any serious concern. Human error, however, is another matter. As with any test, if the sample is mishandled the results can be incorrect. Blood samples, due to the amount collected and method of collection, are least prone to contamination or mislabeling.
Those who do their own sampling, via cheek swabs or hair pulls, need to follow the directions provided and take care that each sample is packaged and labeled before the next is collected.
At present, there is no standardized marker set for canine paternity testing. Each lab uses different markers, so comparing results from one to the other is comparing bananas to fleas or pears.
If your dog was tested at one lab and he’s bred to a bitch tested at another, the pups would have to be tested at both labs to verify each parent separately. If the owner of a pup wanted to use a different lab than either the bitch or stud owner,the results would be meaningless because there would be noting to compare the puppies’ results with.no test currently available can tell anyone everything about a dog’s genetic makeup. It is unlikely that such a test will be available for many years. There is no way to completely clear any individual dog of carrying unwanted genes.
Understanding what markers are and why they are used is also important. Markers are not genes, but sequences of DNA that occur at specific places (loci) and, ideally, have several different forms (alleles.) Each locus will be given a designation (A, B. C, etc.), as will each allele (1, 2, 3, etc.). The designations are not detailed descriptions of the markers, those would
looks something like this: TCAGGGACCTCAGCAGCAG…. only very much longer. Now you can understand why they use a shorthand designation. In the case of paternity testing, the sire’s and dam’s markers are compared to the pup’s. If the pup has markers that could not have come from one (or both) of its parents, then its breeder was either very sloppy or dishonest.
The use of multiple markers eliminates the need to worry about mutations causing a mismatch. One marker might have changed, but two is unlikely , and mutations in more than that at the same time is so improbable that
it can be dismissed as a practical impossibility.
DNA testing for paternity and disease will become the norm . But now, while it’s still so new, the dog-breeding fraternity of this new tool need to read the “labels” carefully so they understand what it is– and isn’t, and what it can– and can’t– do.