Bearded Collie Article
In Breeding and the Bearded Collie
By Wendy Hines
Ramsgrove has a policy of making the most of the available
gene pool. To do this we are forging links with breeders
throughout the world. We have
already imported several Beardies
and this policy will continue.
Small Gene Pool
Beardies derive from a relatively
small gene pool and, like all
pedigree animals, have an inevitable degree of inbreeding.
Founder breeders were often obliged to mate very close
relatives such as father and daughter, brother and sister
because they simply didn’t have much choice. The surprise
is that whilst such close matings are relatively rare today the
average inbreeding rates are significantly higher than they
were in those early eight – ten generations.
These days there are several computer programmes that cut
out the mathematical challenge and make it possible to find
the inbreeding co-efficients – basically the degree of
inbreeding - for any dog at the touch of a button. Some
breeders may baulk at the study of such figures but such
Luddite-like attitudes are usually founded in ignorance and a
lack of understanding of the benefits the
appropriate use of science can bring to
pedigree dogs, not only in producing
outstanding specimens for the ring but also,
and perhaps more importantly, healthy
family pets.
I was very pleased to attend the Kennel
Club's 2012 Breeder's Symposium which covered aspects of
genetics, DNA testing and breeding for healthI was
particularly pleased to hear Dr. Lorna Kennedy, senior
scientist at the Centre for Integrated Genomic Research at
the University of Manchester. Dr. Kennedy spoke at a
Beardie Health seminar earlier in the year and some of her
material related to Beardies. She has spent the past 20
years working on the Major histocompatibility Complex
region of the genome in dogs and wolves. The MHC plays an
important role in the immune system of all mammals and, as
in humans, MHC associations have been identified in most
canine auto immune disease. Within the MHC there is a
region called the Dog Leucocyte Antigen (DLA), a set of
three variable polymorphic genes that are inherited from
each parent. These sets are referred to as haplotypes and, in
line with most breeds, Beardies have about five different
haplotypes. Also in common with other breeds, one of these
haplotypes is more common than the others. In Beardies this
is haplotype 1 and is carried by more than 40 per cent of the
breed. Haplotypes can predispose a dog to developing a
particular auto immune disease but act as a 'protective'
against it developing another. Haplotype 1, for example, is
thought to be a risk factor for SLO but seems to be protective
against Addison's disease. Haplotype 3 appears to carry
greater risk for the development of Addison's disease and, in
many breeds, haplotype 4 has been implicated with auto
immune haemolytic anaemia.
Sadly all this information does not mean we can go test our
dogs for their haplotype status, breed accordingly and live
happily ever after.
The haplotypes do not work on their own but are affected by
around 40 other genes and by all important environmental
factors such as viruses. If a dog has all the genetic markers
to predispose it to a particular disease but is lucky enough
never to encounter the trigger factor it will remain healthy.
And a dog with a haplotype that predisposes it to a particular
disease but without the multiple other genes involved will
also remain unaffected even if it encounters the virus.
Dr. Kennedy explained that is was very unlikely that there
would be a genetic test that would advise breeders on which
dogs would produce AI disease. The most we can hope for is
a test that will give a percentage risk of what a dog will
produce. Percentages can be difficult to work with. A ten per
cent chance of venturing out in the rain without a coat and
getting caught in a shower might seem a much less risk than
having one puppy in a litter of ten destined to suffer a
dreadful disease. We might even find ourselves in the
position of having to evaluate, for example, the risk of
developing hypothyroidism, which is relatively easy to treat
and manage and the risk of developing Addison's disease
which, whilst manageable, can have more devastating
effects.
Dr. Kennedy emphasized the importance of maintaining all
haplotypes. A common haplotype is probably common for a
good reason - it give protection. A rare haplotype might be
rare for a good reason, being detrimental to the dog. At the
moment we don't know enough to take the huge risk of trying
to eliminate any haplotype. It would probably be a good idea
to breed dogs with a particular haplotype to dogs with an
alternate set. However, testing is expensive and the best
offer would be testing a batch of 100 dogs for around £5,000.
It is interesting that the same haplotype can have different
effects in different breeds. Although we should be working to
make the best of our gene pool we must also consider the
fact that introducing a 'new' haplotype might also introduce
diseases that we currently don't have. In the same way,
working to increase the incidence of a minority haplotype
might have the unwanted effect of increasing the incidence
of a disorder that is currently rare.
What is Breeding?
Inbreeding is not always easy to identify and it is vital to
study pedigrees spanning at least eight generations to gain
an accurate analysis. An animal which appears to be
outcrossed, with no individual ancestor appearing more than
once in a three generation pedigree, may descend from only
four animals and therefore be highly inbred. The inbreeding
coefficient is an estimate of the percentage of all the variable
gene pairs that are homozygous – that is identical - due to
inheritance from common ancestors. Co-efficients also
pinpoint the key ancestors that feature in the inbreeding and
give an estimate of the contribution they are likely to have
made.
The mating of an otherwise unrelated half brother to half
sister will produce an inbreeding co-efficient of 12.5 per cent
while a brother-sister or father-daughter mating will give
inbreeding co-efficients of 25 per cent. Very few Beardies are
produced from such close matings but many have similar
and even greater degrees of inbreeding because of the
influence of background inbreeding, the intensive use of
niece-nephew, uncle-niece and similar matings.
Popular Sires?
Two of the most influential stud dogs of the seventies and
eighties were Ch Orora’s Frank and Ch Pepperland Lyric
John at Potterdale. Both dogs were super Beardies, different
in type, but both great dogs. Their lines have combined to
produce many of today’s top winners. Both dogs consistently
produced high quality offspring that went on to produce well
themselves.
Inbreeding co-efficients for most current stud dogs are very
much higher, with figures of more than 20 per cent at
generation three rising to more than 27 per cent at
generation eight being far from exceptional. Whilst at first
glance such dogs might not appear to be particularly inbred
they are only as genetically diverse as offspring from father –
daughter combinations.
Such breeding can and does produce top class dogs, but
breeders need to be aware it is happening so that they are
able to make informed choices
These two dogs, and most of their generation, shared a
similarity that sets them apart from most of the current
leading stud dogs. They were far less inbred.
Frank was from Ch Osmart Bonnie Blue Braid and Ch
Willowmean Mignonette at Orora, top ranking dogs and
bitches of their day. His co-efficient of inbreeding at
generation three was 0.00 per cent, rising to 0.78 per cent at
generation eight.
Lyric John was by Wishanger Buttertubs Pass by Quinbury
ex Pepperland Pandamonium and more closely bred, His co-
efficient of inbreeding at generation three was 0.00 per cent,
rising to 8.59 per cent at generation eight.
What does in-breeding do?
Just as genes responsible for undesirable characteristics
may be bred out by inbreeding, so can genes responsible for
undesirable defects be bred in. In the Birman cat, for
example, inbreeding co-efficients average at between 40 and
60 per cent and the breed is affected by hereditary
conditions including kidney dysfunction and liver shunt.
Persians can suffer an inherited defect to the walls of blood
vessels, Siamese are susceptible to an inherited disorder
causing a blockage to part of the stomach and British
Shorthairs are prone to a blood clotting disorder.
In many instances careful selection by breeders can prevent
dogs carrying abnormalities being used in the breeding
programme and this can substantially reduce the risk of
undesirable characteristics being established by inbreeding.
Sadly, this is not always possible. The Beardie, for example,
is a generally very healthy breed but there does seem to be
an increasing incidence of dogs affected by low thyroid
problems and diseases of the auto immune system. Such
disorders do not usually become evident until the dog has
reached middle age, years after the affected individual has
been used in a breeding programme.
Laboratory mice are probably amongst the most inbred
animals. Scientists have aimed to produce mice that are as
genetically identical as possible as this increases their value
in experiments. Many such mice are perfectly healthy
animals, but they must be kept in sterile environments as
their immune systems are unable to cope with the everyday
germs which pet and wild mice would shrug off with no ill
effect. Extreme inbreeding has severely reduced the diversity
of genes needed to ensure an efficient immune response
and the laboratory mice can be dangerously compromised
by trivial infections that would otherwise be of little concern.
Each dog has 38 pairs of chromosomes plus the x and y
chromosomes. Each chromosome carries genes made up
from the DNA that is the genetic building brick of inheritance.
Each parent contributes one of each pair of chromosomes.
When dogs have multiple appearances in a pedigree they
will have contributed a correspondingly greater number of
their chromosomes and there is an increased chance that
any single chromosome pair is identical due to inheritance
from this common ancestors. Inbreeding increases the
number of identical genes carried by the dog. An inbreeding
co-efficient of 10 per cent, for example, indicates the
probability that 10,000 of the 100,000 genes on the dog’s
chromosomes have identical alleles. A co-efficient of 25 per
cent indicates that 25,000 of the 100,000 genes will have
identical alleles.
Is In-breeding Bad for the Breed?
There is nothing intrinsically wrong with inbreeding, but
breeders must be aware of the risks and benefits of
producing stock with high inbreeding co-efficients. The first
step must be to become aware of the degree of inbreeding
within a particular kennel, especially where that inbreeding is
background and not apparent without careful study of the
pedigree. The use of inbreeding co-efficients, whether
calculated manually or at the touch of a button on a
computer, is a vital tool in assessing inbreeding rates and
one that merits far greater application in the world of
pedigree dogs.
Ramgrove's top producing sires, Ch Gillaber Drummond and
his son Ch Diotima Sea Wolf at Ramsgrove, are no longer at
public stud and their young dogs are only available to a
limited number of bitches.
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