By George Packard
High anxiety about
genetic diseases comes with the territory for anybody who is considered
to be a responsible breeder these days. In fact, if you are breeding
dogs, and you aren't worried about genetic disease, you'd better hold
off on that next mating until you've done your homework.
estimate that the average purebred dog is carrying at least 4-5 defective
genes. To put it another way, when you are looking at that gorgeous
champion with normal hips you are also looking at a dog who is carrying
the genes that can cause several types of genetic disease.
And unless his owner
has a detailed genetic pedigree on this dog and is willing to share
it, you have no way of knowing what those disease genes are.
That champion may
be carrying a recessive gene for PRA, and if he's bred with a bitch
who is also carrying the PRA gene, the disease will show up in the puppies.
And even though he has normal hips, he may be carrying some of the recessive
genes involved in hip dysplasia. If you mate him with a bitch who is
normal but also carrying recessive genes for dysplasia, you'll suddenly
find yourself, heartbroken and bewildered, with dysplastic puppies.
"I'm not worried,"
you may say, " because soon we'll have DNA tests that will solve
That's all well
and good if researchers have developed a test for the single gene disease
your line is troubled by. But if that test doesn't exist, are you willing
to wait five or ten years for your turn to come? And that's assuming
you'll persevere as a breeder beyond the six-year average when most
people give up, often because they can't seem to stop producing puppies
with genetic diseases. Of course, we are only talking about tests for
diseases. Most of the severe diseases like hip and elbow dysplasia,
cancer and epilepsy, are polygenic, caused by the complex interplay
of many genes, and no researchers have come close to developing a polygenic
Are you willing
to wait 20 years for a gene test for hip dysplasia? Are you willing
to watch another 30 years go by with no significant decrease in hip
dysplasia among purebred dogs?
Breeders in Sweden
in 1976 weren't willing to wait, and so they set up an open registry
and started screening all their dogs. By 1989 they had achieved a 50
percent decrease in moderate to severe hip dysplasia in almost all
breeds ("Breeding Healthier Dogs in Sweden": Ake Hedhammar,
Tijdschriftvoor Diergeneeskunde, April 1991).
What is the secret
of this astonishing success? Nothing more profound than the fact that
each breeder made it his or her business to find out where the carriers
and affecteds were in a dog's close family, siblings, half-sibs, offspring,
parents and parents' siblings. Using relatively simple methods, they
could then predict the risk of inheritance of defective genes in any
A few breed clubs
in the US have shown similar successes with targeted genetic diseases.
But the majority of our purebred dog breeders, and the major institutions
that support them such as AKC and OFA, have shown little or no interest
in using open registries combined with proven breeding methods to reduce
Times are changing,
however. In 1990 GDC (Institute for Genetic Disease Control in Animals,
www.vetmed.ucdavis.edu/gdc/gdc.htm) established an international all-breed
open registry based on the success of the Swedish model. In the following
decade thousands of breeders began to register their dogs and to make
breeding decisions in accord with the knowledge of where the carriers
and affecteds were in a particular dog's family.
Recently, GDC started
an advocacy campaign to call for the widespread use of open registries
and appropriate breeding methods. The strong response they are getting
from breeders throughout the purebred community confirms that the demand
for open registries is increasing rapidly
But the reality
is that no open registry, whether it is the international GDC registry,
or an open registry set up by a breed club, can be useful until it contains
significant number of dogs registered in close family groups. Detractors
of the open registry concept point to this weakness but ignore the fact
that even without enough information in an open registry, breeders can
still make progress against genetic disease by doing the legwork themselves.
What can you do?
-- Register your
dogs in an open registry and urge every breeder you know to register
-- Do whatever you have to do to find out where affecteds and carriers
are among a dog's siblings, offspring and other close relatives.
-- Don't breed to a dog whose owner will not supply that information.
Screen as many of your own dogs as possible, and supply that information
to buyers and breeders.
-- Contact your breed's health committee, the AKC and OFA and strongly
urge them to actively promote the use of open registries.
-- Urge your health committee to put GDC on the list of approved registries.
For specific information
on breeding methods and genetic disease, start with these books:
Control of Canine
Genetic Diseases; George A. Padgett, DVM, Howell Book House, New York,
Genetics of the
Dog; Malcolm B. Willis, Howell Book House, New York, 1989
Several very good
articles on basic genetics for dog breeding:
Article by George
((c) 2001 George Packard) (Permission for noncommercial electronic
distribution granted. Contact author for permission to reprint).
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