2017 Nov Dec

single litter of 6-12 pups you can get almost
any result.
When you have DNA test results on
both dog and bitch you don’t have to worry
about what the grandparents test results
were because you know the genotype of
parents. If a dog is N/N, it did not inherit
the mutation at all, no matter whether one
or both of its parents were carriers.
Yesterday a 3.5-year-old dog I bred was
diagnosed with corneal lipid dystrophy.
Eye doctor specialist said that typically
it does not get any worse and he should
be able to do agility. That’s good, but
what about breeding? Do you know if
it is recessive or dominant? I have been
breeding dogs with these lines for about
15 years and have never had this problem.
Inherited corneal dystrophy is
extremely rare in Aussies if it occurs at
all. However, non-hereditary corneal
degeneration (which isn’t a precise term and
might sometimes be called a “dystrophy”),
while not common, is reported from time
to time. I suspect this is what you’re your
dog has since the vet specified “lipid
dystrophy.”
In corneal degeneration either or
both eyes develop lipid (cholesterol) or
calcium deposits. These are a secondary
effect of other diseases including uveitis,
glaucoma, luxated lens, Cushing’s
Syndrome, hypothyroidism, or diabetes.
Diets too high in fat can also be a cause,
as is old age – particularly where there
are other serious underlying health issues.
Sometimes it isn’t clear what the cause is. If
the dog is otherwise healthy, go ahead and
breed. However, if it does have one of the
diseases that can cause this keep in mind
that several of them are inherited.
I am trying to understand the MDR1 gene
as a breeder. Say a bitch has 2 copies,
could I breed to a dog with one? How
many genes would the resulting pups
have? What about same bitch to a stud
that’s clear? What problems would be
caused should you breed parents each with
1 copy? Or each having 2 copies?
Dogs that have the MDR1 mutation,
even two copies of it, may be bred (except
in some European countries where this
is banned). The mutation wouldn’t
be a problem at all if dogs were wild
animals, which don’t go to the vet and get
prescriptions. The test result is largely an
Q&A
advisory that your dog may have serious
reactions to some drugs, even if it has only
one copy. (Dogs with one copy react, but
at a higher dose.) Keep in mind that there
are many things – most likely including
other genes – that can cause drug reactions.
MDR1 happens to be the one we can
identify ahead of time.
View this mutation as a fault. Ideally,
you do not want to breed a dog that has it,
whether one or two copies, to another that
also has it. However, depending on the
various virtues and faults of two MDR1
dogs, you might have good reason to breed
them to each other. Let’s say your girl’s uncle
was diagnosed with hemangiosarcoma
(HSA), a lethal cancer. You definitely want
to breed away from that, but HSA is also
a relatively common issue in the breed. If
your choice among suitable sires comes
Project:
Goal:
Conducted by:
Canine Epilepsy
Featured Research
To identify genes responsible for causing epilepsy in various breeds
of dog, including the Australian Shepherd, and develop a DNA
screening test.
Dr. Ned Patterson
Canine Epilepsy Network
University of Minnesota
Samples needed from: Purebred Australian Shepherds:
• Dogs affected with epilepsy
• Siblings of affected dogs
• Dogs 6 years of age or older with no history of seizures
Sample type:
Contact:
Note: the need for samples from epileptic dogs is acute. If you have an
Aussie with epilepsy, please submit a sample to this study.
Whole blood in EDTA tubes.
Sample submission forms and seizure survey can be found here:
www.cvm.umn.edu/vbs/faculty/Mickelson/lab/ie/home.html
Katie Minor
Neuromuscular Genetics Lab
University of Minnesota
C339 Veterinary Teaching Hospitals
1352 Boyd Ave.
St. Paul, MN 55108
612-624-5322
minork@umn.edu
down to one that had a close family history
of HSA and one with ho HSA in the family
but a double-dose of MDR1 mutation, use
the dog with the MDR1 mutation. Puppies
can be tested and their owners advised on
what to do to avoid the dog getting the
wrong meds.
On the matter of what you would get
with various breedings, if your girl is M/M
then all of her puppies will have at least one
copy of the mutation from her. If you breed
to a clear dog then each puppy will have
one. If you breed to another M/M then all
of the puppies will be M/M because neither
parent has anything else to give them. A
M/M bred to a M/N would produce puppies
that are either M/M or M/N but you won’t
know which without testing them. M/N to
M/N can give you any result. M/N to clear
gives you clears or M/N.
For information on other studies looking for samples from Aussies, go to:
www.ashgi.org/home-page/how-you-can-help/research-support/current-research-for-aussies
70 AUSSIE TIMES November-December 2017