IN 2006, TWO SCIENTISTS CLARK AND MURPHEY OF TEXAS A & M UNIVERSITY IDENTIFIED AND SEQUENCED THE CANINE GENE FOR MERLE. THE MERLE GENE WAS FOUND TO BE CAUSED BY A MUTATION IN THE GENE CALLED "SILV". THE WAY THE MUTATION OCCURS IS CALLED RETROTRANSPOSON. THIS IS TE ABILITY FOR THE PIECE OF YOUR DOGS DNA TO ACTUALLY JUMP OUT OF THE GENE IT HAS INFECTED DURING CELLULAR DIVISION AND GENETIC DNA REPLICATION. WHEN THE MELANOCYTES (BLACK PIGMENTATION GENES) ARE MIGRATING FROM THE NEURONAL CREST DURING THE EMBRYONIC DEVELOPMENT OF THE DOG, THE MERLE GENE REMOVES ITSELF FROM THE MELANOCYTE GENES (BLACK PIGMENTATION GENES) AND INVADES AND INFECTS THE EUMELANIC GENE (THE GENE THAT PRODUCES BLACK, BLUE, GREY AND DARK BROWN AREAS IN THE COAT)
WHICH MEANS, THAT THE MERLE GENE IS AN INCOMPLETE DOMINATE DILUTION GENE. THIS GENE IS A PATTERN MODIFIER OF WHATEVER COLOR GENES THE DOG IS CARRYING. IT CREATES A BREAK IN THE COLOR PATTERN, CAUSING THE COLOR TO DILUTE IN SOME AREAS, WHILE LEAVING DARKER COLORED SPOTS IN OTHERS.
THIS MERLE GENE IS A DOMINATE GENE THAT IS NOT CARRIED RECESSIVELY. ONE PARENT HAS TO BE A MERLE IN ORDER TO GET A MERLE OFFSPRING. IF THE OFFSPRING HAS THE MERLE GENE THAN IT WILL EXPRESS ITSELF. (ON AVERAGE, HALF A LITTER WILL BE MERLES) IT IS IMPORTANT TO REGISTER THESE MERLE PUPS AS MERLES ON HIS/HER PAPERS.
A "CRYPTIC" OR "HIDDEN" MERLE HAD VISABLE MERLE MARKINGS AT BIRTH, BUT AS THEY MATURED THE MERLE MARKINGS DISAPPEAR. THESE DOGS ARE STILL GENETICALLY MERLES AND WILL PRODUCE MERLE OFFSPRING WHEN BREED. SO, IT IS VERY IMPORTANT TO REGISTER THESE MERLE PUPPIES AS MERLES ON HIS/HER PAPERS. (IT WILL ALSO HELP TO PREVENT TWO MERLES BEING BRED UNKNOWINLY)
IT IS VERY IMPORTANT TO NEVER BREED "TWO MERLES" TOGETHER. BREEDING MERLE TO MERLE YOU MAY PRODUCE PUPPIES THAT HAVE HEARING LOSS, VISION PROBLEMS, INFERTILITY AND OTHER SERIOUS PROBLEMS.
SOME HAVE SUGGESTED THAT MERLE APPERARED IN THE CHIHUAHUA BREED FROM ACROSS TO ANOTHER BREED, SUCH AS THE DACHSHUND. OTHERS HAVE SUGGESTED THAT THE GENE HAS BEEN PRESENT FOR MANY GENERATIONS, BUT THE DOGS WERE INCORECTLY REGISTERED ON THEIR PAPERS, SUCH AS BLUE AND TAN OR BLACK AND SILVER.
THE MERLE GENE IS PRESENT IN CHIHUAHUAS, SHETLAND SHEEPDOGS, AUSTRALIAN SHEPHERDS, COLLIES BORDER COLLIES, CARDIGAN WELSH CORGI, DACHSHUNDS, GREAT DANES, CATAHOULA LEPARD DOG, NORWEGIAN HOUND, AND THE PYRENEAN SHEPHERD..
AFTER CAREFULLY CONSIDERING THE MULTIPLE PETITIONS PUT FOURTH BY THE ANTI-MERLE SECTOR TO DISQUALIFY THE MERLE CHIHUAHUA AND THE EVIDENCE REGARDING THE BREEDING OF THESE DOGS, ALONG WITH THE DESIRE OF THE MAJORITY OF ITS MEMBERSHIP, THE CHIHUAHUA CLUB OF AMERICA HANDED DOWN ITS FINAL DECISION TO FULLY ACCEPT THE MERLE CHIHUAHUA.
THE AKC STAND STATES: THAT THERE IS NO DISQUALIFYING FOR COLOR OR PATTERN WITHIN THE BREED. IT STATES THAT ANY COLOR SOLID, MARKED OR SPLASHED IS PERMISSIBLE.
THE AKC DEFINITION OF MERLE: A MARKING PATTERN, USED IN CONJUNCTION WITH ANOTHER COLOR, THE COLOR IS CHARACTERIZED BY A MARBLING EFFECT OF DARK PATCHES AGAINST A LIGHTER BACKGROUBD OF THE SAME COLOR.
FOR MERLE TESTING: http://www.genmarkag.com/home_ companion.php
BY TESTING DOGS FOR THIS GENETIC TRAIT, IT IS POSSIBLE TO:
1. ALLOW IDENTIFICATION OF THE MERLE DOGS TO PREVENT MERLE TO MERLE BREEDING2. CLASSIFY CHIHUAHUAS AS SINLE OR DOUBLE MERLE.3. IDENTIFY CHIHUAHUAS THAT ARE HARD TO SEE AS MERLES. (CRIPTIC / HIDDEN MERLE)4. IDENTIFYHEAVILY TICKED CHIHUAHUA COAT COLOR FROM MERLE PATTERN GENE.5. ALLOW THE OWNER OF THE CHIHUAHUA TO PROPERLY REGISTER THEIR DOG WITH "MERLE" IDENTIFIED ON THEIR PAPERS.MERLE FACTS: http://www.cejaschihuahua.com/merlefacts.html
I.D. OF THE MERLE GENE: http://www.fags.org/patents/20080227102
