Common
autoimmune conditions include autoimmune hemolytic anemia, sebaceous adenitis,
diabetes, inflammatory bowel disease, and the most common of all, autoimmune
thyroiditis to name just a few. Anyone
who has been on the pet H Havaneselists has heard of all of these and more in
our breed. If there is one case we know
about, there are probably many, many more.
So, is this something we should be concerned about as breeders? And, if so, what do we do about it?
First,
let’s look at other breeds that have similar problems including the Standard
Poodle, and the Italian Greyhounds. What have they done? The department of genetics at UCDavis under
the guidance of Dr. Niels C. Pedersen has developed a gnome wide genetic
diversity test geared specifically for the standard poodles and the Greyhounds:
How this works and what is different to the other
services that have been offered is that while the UCDavis study looks at the
entire gnome, it also pays particular attention to the MHC (major
histocompatibility complex) which contains many of the genes that protect our dogs
from external assaults such as viruses. The
MHC of dogs is commonly known as the dog leukocyte antigen (DLA) complex.
But
sometimes an immune system goes crazy and can’t tell a foreign body like a
virus, from the animal’s own cells. The
result may be an auto (self) immune condition like those mentioned above.
Why
this is most challenging for breeders is twofold. We may see different conditions in different
litters or even in the same litter and not realize that what causes them may be
related. While one dog may have
thyroiditis, another may suffer from SA (sebaceous adenitis). The second
problem is that many of these conditions tend to occur in the more mature dogs
and most need to have some type of trigger.
So even in two genetically identical clones, one may experience
thyroiditis and the other not.
So
what can we do about it? The propensity
to develop an autoimmune disease is associated with a general lack of genetic diversity,
as witnessed by the fact that they occur far more frequently in pure-breeds
than random bred dogs. They also tend to occur with greater frequency and
clinical form as a breed becomes more inbred.
Autoimmune diseases are
genetically complex and involve the whole genome, and not just the DLA. So how do we maintain a diverse immune system
in our dogs and still maintain the characteristics we want, the beautiful
structure, coat and personality of our breed?
One way is to build a picture of the Havanese genome to see what genes
we actually have across the entire genome, as well as in the DLA complex. Once
we know that, then by testing all potential mating pairs, we can ensure that
while maintaining the quality and structure we want for our dogs, we can also ensure that each new breeding
brings us as much diversity as possible. But aren’t we doing that using COI
(Coefficient of Inbreeding) to guide us?
COI simply shows us the probability that any two dogs are genetically
similar or dissimilar. With genetic
testing we have a much more accurate idea of the diversity level of any mating
pair.
First,
however, we need to find just what set of genes exist within our particular
breed and to do that we can take advantage of the program at UCDavis developed
in conjunction with the Standard Poodle,
Italian Greyhound, Alaskan Klee Kai
breeders have also started studies through UCDavis. Several more breeds are
also considering genetic diversity testing.
There
is a group of people who have already joined together to try to see this
accomplished. You can find out more about them through the Facebook group- HavaneseGeneticsUCDavis, whose members are from almost every country where Havanese
can be found. You may also contact me as
coordinator for North America or Senija Hodzic in Holland who is responsible
for the European segment of the Havanese population.
The
goal is to find every unique gene so that we know what we have to work with. To get
started we need as diverse a sample population as possible which includes
Havanese from all countries where they exist, and from all the unique lines
within those countries. Many dogs from the same breeder or family is not the
goal in this initial step. We need at
the very minimum 100 dogs, but 400 would be better. The initial cost will be $50 per dog and some
volunteers are already working on gaining financial assistance where needed. The goal is to find every unique gene that
exists within the world-wide family of Havanese. Once that is achieved then genetic analysis
will be made available so that each breeder with be able to judge the diversity
level between possible breeding pairs and hopefully choose the dogs found to be
the most diverse.
