please read the article regarding merles. they may answer questions you might have. My breeder and personal friend, who has been showing and breeding chi's for more then 20 plus years, is very seriously thinking about not breeding and chow chis's due to the merle impact on the bred. and how difficult it is to find quality animals without merle somewhere in the pedigree. In europe merles are band from the show ring and not recognized as a bred color. unfortantualy many many many breeders disagree with that the merle gene has no affect on the bred, so they continue to use them in their breeding program. for exactly some of the reasons posted. i stress that this is my opinion on merles. and I am only sharing information, for individual education. Everyone can form their own opinions based on facts. all the best,Amie
--- On Mon, 11/17/08, [email protected] <[email protected]> wrote: From: [email protected] <[email protected]> Subject: merle To: [email protected] Date: Monday, November 17, 2008, 10:56 PM ------------------------------ http://www.genmarkag.com/canine_faqs.php Health Problems Associated with the Merle Allele Both heterozygous merle (Mm) and homozygous double merle (MM) dogs may exhibit auditory and ophthalmic abnormalities including mild to severe deafness, increased intraocular pressure, ametropia, microphthalmia and colobomas. The double merle genotype may also be associated with abnormalities of skeletal, cardiac and reproductive systems. Health Concerns Increased Intraocular pressure: excessive pressure created in the eye. Ametropia: vision impairment due to a refractive error such that images fail to focus upon the retina. Microphthalmia: a smaller than normal eye due to a defect occurring early in development. Affected dogs may have prominent third eyelids. Other eye defects are common in animals with this condition, including defects of the cornea, anterior chamber, lens and retina. Coloboma – a defect in ocular tissue; a cleft or missing portion of components of the eye, most commonly affecting the iris. -------------------------------- http://www.kandeechihuahuas.com/merles/ftlowille.html ----------------------------------------- The Chihuahua standard reads, "any color--solid, marked, or splashed." This refers to color, not modifiers that act on color. The merle gene is a modifier producing a pattern, not a color--the merle gene modifies, or acts on, any color it is paired with. Deafness and/or blindness (partial or complete) has already been proved to be associated with a single copy of the merle gene in Chihuahuas . Once this foreign gene gets into our light colors (fawns, creams, white-spotteds, etc.), it will not be detectable to the eye and it can easily creep into any line through an outcross. Color pedigrees will not help since many puppies change color as they grow and are not registered correctly. Merles & Genetics For those who are not familiar with the merle gene, one fact is indisputable: In order for a dog to BE a merle, it MUST HAVE one merle parent, either sire or dam. This gene cannot remain 'hidden' for generations, like chocolate or blue, which are recessive colors, thus proving that it has only recently been introduced into our breed. A merle dog (Mm genetically) contributes one of these genes when bred, either M (merle) or m (non-merle). If a puppy receives the M (merle) gene, it will be merle. If it receives the m gene, it will not be merle. The M (merle) gene acts on whatever coat color the puppy has. The problem with allowing the (new) merle color in Chihuahuas , is that we have so many light-colored dogs. Breeding these light dogs to merle will result in fawn, cream, red, sable, white, etc. merles, which are often NOT recognizable as merles as adults(though when bred to black tris, they will produce blue merles, thus identifying one parent as a hidden merle). When these hidden merles are bred to other merles (accidentally or unknowingly), thus doubling up on the merle (M) gene, the result (if the puppy inherits one M--merle--gene from each parent) will be a puppy with two M genes--a homozygous merle. These puppies will be deaf and/or blind, and some will have other internal health problems as well as possibly being infertile. The fact that they are deaf and/or blind will not be recognized until they are older (around weaning time), hence a decision will have to be made about what to do with them.... At this time, there are already normal (single M) merle Chihuahuas which have been diagnosed by two independent veterinarians with deafness and eye problems that will lead to blindness. Is this really for the betterment of the breed? The Inheritance of Coat Color in Dogs, by Clarence Little, when listing colors for Chihuahuas , does NOT list MERLE. ----------------------------- "The Trouble with Merle" Interesting article http://www.asca.org/Education/Advanced/troublemerle.htm ____________________________________________________________ Click for FHA loan, $0 lender fees, low rates & approvals nationwide
