Dog breeding and Ethics
Human tamed wolf about 15,000 years ago.
It took another 10-12000 years to breed the 10 progenitor racial groups
identified by the researchers are seeing dogs, scented dogs, work and guard
dogs, water Spaniels and Retrievers, Pointers, Terriers, herding dogs and small
dogs.
The sight hound, specialized for coursing game, is thought to have emerged in
Mesopotamia around 4000 - 5000 BC. Modern breeds like Greyhound and Afghan are
found at the end of this branch of the dog's family tree.
The scent hound emerged around 3000 BC, characterized by a highly sensitized
sense of smell . Bloodhound, Foxhound, and Labrador are all believed to have
descendent from this dog.
Working and guard dogs appeared likely to emerge in Tibet about 3000 BC, with
modern descendants that Rottweiler, St Bernard's and Bulldog. At about the same
time, emerged seemingly small companion dogs up in Malta. Modern descendants
include Poodle and Pug.
It took another 3-5000 years for man to grow up the approximately 300 purebreds
we know today. Total from the biggest of breed to the smallest of them, 99% of
the DNA' is common to all races. We tend to think of them as very different
because of the large variation in size and appearance, but the genetic
difference is minimal.
This is a family tree it is important for all us breeders to keep in mind,
human has through thousands of years inbreed the dog. All purebreds dogs today
are a result of this relatively narrow starting point. Today we have
approximately 400 million dogs in the world. Dogs have been our closest
companions through thousands of years.
More than just our servants, they are a human-made spices that has evolved in
harmony with us and our wishes for features and exterior. Genetic martial behave
the same way be it human or dog. Through generations of breeding from dogs that
derived from the same ancestors, mutations occur in the DNA and can continues as
an inherited disorder. We are often concerned about what is inherited and what
is not, the answer is EVERYTHING is potentially inherited. Chromosome is
responsible for determining the form and function, for every living organism.
Genes are placed on these chromosomes. Genes are composed of DNA
(deoxyribonucleic acid) - the basic building blocks of living things. DNA looks
a bit like a long string of beads , two in each pair. Dogs have 39 chromosome
pairs (78 chromosome in total). The first 38 chromosome pairs are numbered
pairs, in each pair one bean from the mother and one from the father. The 39th
pair is the gender-chromosomes this pair has some inheritance but also something
unique for each individual, such as gender and personality. Each individual has
several defective chromosomes, these are usually overridden by the fresh bean 2
in the DNA pair and the individual is not affected by these. It happens once in
a while for even the most ethical and experienced breeders, that they combines
two individuals with the same defective chromosomes. The result can then be 3
variations in the offspring -25% genetically healthy, 50% carriers of gen defect
and 25% affected of defect. Some diseases are the result of several defective
chromosomes. In more rare cases the chromosome defect is dominant and continued
despite the fact that the other party does not have the defect. Chromosome
defects can also be on the gender chromosomes, in this case the disease affect
only a gender of the offspring . The same disease can therefore be inherited in
different ways depending on where in the chromosome the defect lies. An example
is the multi gen disorder PRA, which can have all of the above genetic heritage
variants. So far, "loci" ( the numbered gen placement) have been identified for
six forms of PRA, the researchers expect to find at least twice as many in the
years to come.
Among top ten diseases in purebred dogs several that are of interest for human
diseases are included like ;cancer, epilepsy, autoimmune diseases, blindness,
cataracts and heart diseases. Dogs suffer from more than 400 genetic diseases
and daily new ones are discovery. Many of these are similar to human conditions.
Modern purebred dogs equal geographically isolated human populations, except dog
breeds are more extremely isolated. This makes them uniquely valuable in
relation to the understanding of mutations in human genes. Genes responsible for
these is probably constant for humans and dogs. It is used millions of dollars
on research of disease in dogs, because this knowledge benefits human in the
form of treatment for our hereditary disorders. Today, much of the dogs "loci"
is mapped, and in some cases identified for several of these diseases: kidney
cancer, narcolepsy, Rheumatoid arthritis, keratin-associated diseases, bleeding
disorders, epilepsy, heart, allergies, retinal disease and cataract, and copper
toxicosis. Some of these breakthroughs in the research will also benefit our
dogs in the form of treatment, or knowledge about ways to breed diseases away.
But with unpredictable genetic mutations new and unknown diseases will occur.
These can potentially be much more damaging than the ones we bred away. It is
also important to remember that mutation is not only negative. Mutations can
have positive, negative, or no effects. Most mutations are neutral (have no
effect), some are negative (decreasing an organisms chances of survival and
reproduction) , and some are positive (increasing an organisms chances of
survival and reproduction).One thing is 100% sure - disease and defects are part
of the package in purebred dogs, just as it is in humans.
Breeders around the world, passionately engaged or "their" breed, must deal
with this complex reality. We all want a "breed typical" healthy offspring, and
we all have criteria's for selection of our breeding animals. Through this
selection we create "bottlenecks" for the breed individuals. Moreover,
individuals will be evaluated by judges at the exhibition, whom also has their
own "bottlenecks" for grading the individuals. The consequence is a narrowing of
gen pool in breeds, as well as an acceleration of mutations in the popular
lines. Some breeds are great in number, others are small - some are thousands of
years old, other very young - some are also the big "fashion breed" at the
time. These factors all play a part in how big the end problem will be. When we
think of the age of dog breeds we often forget that the world wars and natural
disasters, only the last 100 years has been very hard setbacks in breed
populations, some have been completely destroyed. One example is: At the end of
world war 1 there were only five dogs of the breed Leon Burger that remained
alive in Europe, and all Leonburgers alive today are believed to be descendants
of those five. Breed Clubs therefore have a great responsibility in relation to
their policies - or rules for breeding. The Clubs main job is the best possible
management of each country's genetic pool - the breed base. The Clubs should
really think through whether a tight regulation, yet a "bottleneck", is really
in the breeds best interest! It is a fact that the highest possible gen pool is
a health benefit for the future. One way to improve this, are mild breeding
recommendations and allowing to blend colour. In dogs as in human, health is more
important than appearance. It is obvious not to use the sick animals in the
breeding, but all our breeding animals are "apparently" healthy carriers of
chromosome defects and mutations, all life consists of both positive and
negative genes. It's the same with humans, every family has their genetic
heritage of good to bad.
What are research findings? These are conclusions after X number of attempts
with the same result. They all have error margins, and are intended for use as
an aid not an absolute fact. Each are what researchers at the time believe to
be the heritage code based on research findings, then 10-30 years later can
prove to be incorrect. An example: researchers on cardiovascular disease in
human vessels. It was assumed elevated cholesterol had a direct heritage through
the generations, those who had it gave it "either -or" to their children. Those
who was not affected did not pass the defect on to their children. This has
relatively recently been shown incorrect, there are carriers that are not
affected of the disease them self - but still can pass this on to their
children.
Individual health information's are often used negatively. One should think
thoroughly through the severity of the defect, before reacting in the form of
restrictions in the breeding of lines after known carriers. In a small breed
populations these individuals are important for the gen pool, as 25% of the
offspring can continuing the lines without the gen defect. A result of strict
breeding regulation can be a narrowing of gen pool, or an increased import of
individuals from other countries. This can increase the gen pool, and thus
enrich the countries breed population - the opportunity is as equally big for
the import of defects the country did not have in it´s breed, in other words,
greater health problem for the country's base.
In the dog world, exhibitions -obedience and other dog sports have been a
great interest for breeders around the world. These provide an opportunity for
an "outside" assessment of a breeders work. Most breeders know that these
results do not say much about the individuals qualities in breeding. A top
show-working dog can be a poor breeding dog, and a poor show-working dog can be
a fantastic a breeding dog. Or one may be really fortunate and have both
quality's in one dog. There are many skilled breeders and judges around the
world that do their best according to the opportunities they have. However in
the dog environment , as in other environments, there is a "downside" - when the
appearance of an individual is a priority over health. We should care less -
breeders and judges - about the missing teeth, ear set, tail set and put more
emphasis on movements, behaviour and signs of poor health.
The organization WSPCA made a documentary regarding this important issue,
witch was shown on BBC in -08 and in Norway in -09. The topic is certainly relevant to this article,
and we add a link to this film. Please note that the content
sheds light to only the "downside", this is not a joyful clip!
www.asterpix.com/console/?avi=18781361
Oddrun Knudsen
Some ref. sources for the article;
http://news.nationalgeographic.com/news/2003/09/0925_030925_doggenes.html
http://www.nature.com/nature/journal/v438/n7069/box/438745a_BX1.html
http://www.newscientist.com/article/dn4682
http://www.geocities.com/retinitis_pigmentosa_rp/r_pigmentosa_genetics.html
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=PureSearch&db=pubmed&term=dog%20breeds%20AND%20genetic%20diseases