Merle Gene in Chihuahuas
After much research and many questions being put to me as a breeder
of Chihuahuas by other Breeders and members of the public regarding
breeding with the merle gene, the following articles and links explain
this lethal gene in lay terms. I hope the following is of some help
especially to people new to our breed.
It should be noted that here in Australia the following wording was
added to The Chihuahua Standard - Smooth and Long Coat by the
Australian National Kennel Control in May 2005 under Coat Colour:
Any colour permissible or mixture of colours except Merle of any
combination. Hence in Australia we cannot register or show any dog
displaying the merle pattern.
Chihuahuas carrying the merle gene cannot be registered nor shown
in Germany, England, Wales, Scotland, and Canada effective January
2008. It was voted upon by the Chihuahua Club of America in Oct 2007
to disqualify the showing of merle Chi's; this decision was sadly
overturned by the membership. I think I can safely say that most of
the world wide Chihuahua Community were incredulous, to say the least,
at this turn of events. Mexico, the country of origin of our Chihuahuas,
does not allow the registration or showing of Merle Chihuahuas.
The Merle gene is a dilution gene that creates a specific coat pattern
it is NOT a colour. It lightens whatever coat colour would otherwise
have been. The dilution is not spread evenly over the coat. It leaves
patches of undiluted colour scattered over the dog's body. The dilution
works primarily on the black pigment in the coat, so any tan or fawn
colour stays even. Black includes liver or chocolate as both of these
colours are dilutes of black.
The merle pattern is completely separate from that of sabling, spotting
or brindling and may or may not include patches of white. Merle is NOT
a mutation. It is a dominant coat pattern (MM or Mm).
For a dog to be merle, at least one parent MUST be carrying the merle gene.
This also means that this gene cannot lie dormant for generations and suddenly
reappear as some overseas breeders have claimed.
Mrs Hilary Harmer, Aztec Chihuahuas (UK), Mrs Thelma Gray, Rozavel Chihuahuas,
Marjorie Fearfield M.B.E. (Bowerhinton), founder of the British Chihuahua
Club in 1949, Mrs Margaret Rider, Rowley Chihuahuas, Miss D Russell-Allen,
Dalhabboch Chihuahuas, and Lady Margaret Drummond-Hay, Seggieden Chihuahuas
to name just a few stalwarts of our breed in the very early days made NO
mention of the merle pattern in Chihuahuas. This suggests only one thing -
the only way the merle pattern was introduced into our breed was to breed
to a dog of another breed that carries the merle gene. Thus the progeny are
mixed breed dogs. To register them as purebreds is both unethical and
illegal.
Most Chihuahua lovers say that Mrs Hilary Harmer, of the famous Aztec
Chihuahua prefix was one of the original "guru's" of our beloved breed,
it is very interesting to note that as early as 1968 she made the following
reference to the merle gene in her book "Dogs and How To Breed Them" (page 9)
under the heading of "Lethal Genes".
"Lethal genes are recessive. The following are some of the lethal genes:
cleft palate, abnormal whelping, haemophilia and bitches, which absorb
their whelps.
"Semi lethal genes, such as those producing bilateral cryptorchids,
eventually become lethal to a breed by resulting in its becoming extinct.
Puppies with cleft palates, unless operated on, cannot suck and therefore
die. The merle colouring is interesting, because it is connected with a
semi-lethal gene, and, when it occurs in a double dose, the offspring may be
blind, deaf or sterile. For obvious reasons, therefore, two merle dogs
should on no account ever be mated together. In fact, it would be better
for merle to be a disqualified colour in all breeds."
Here at Joviva we feel if Mrs Hilary Harmer felt so strongly about the
"merle" pattern all those years ago and the agreement with her by world
authorities the serious consequences it can cause in any breed - we have
to concur that the world wide banning of the merle gene in our beloved
Chihuahuas is a must.
Vivien Cotton
Joviva Chihuahuas
Canberra, Australia
The attached articles should be read to add to your knowledge on this subject
These are some very good links that explain how the merle gene
affects canines:
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