The Merle Gene

Merles are one of the newest trends to hit Chihuahua world with devastating consequences to the breed, merles have been popularized as "rare" or “designer” colors by greedy breeders who are more concerned with money than health.

This particular coat pattern has been introduced by cross-breeding with other breeds. There are no records of Merle Chihuahuas before the 1940's, and therefor believed that it was breed in the line by crossbreeding a chihuahua. This popular merle coat has proved popular and is popping up among other breeds too, but at a loss to the breed as it comes with life changing consequences and health problems. 

Merle DNA

The merle coloring does not occur naturally within the Chihuahua DNA, but the gene is dominant, therefor one of the parents must be a merle for the gene to be expressed. As the merle gene is dominant roughly half of the puppies in a litter with a merle parent will be merle too. This is not a recessive gene that suddenly pops up unexpectedly. The only it way it got into the gene pool was by cross breeding a Chihuahua with another breed.

The merle gene shows up best on black and tan, solid black, chocolate and blue coats. You may also come across ghost merles, they may appear to be cream or sable in color but carry the merle gene in their DNA, their coat appears to be an ordinally Chihuahua with the merle DNA hidden like a ghost.

The Health Risks Linked to Merles

Merles come in a variety of patterns and colors, they usually have blue eyes or one blue eye, this is called heterochromia, and chihuahuas with this will be more sensitive to sunlight. This desired patterned chihuahua comes with more health risks than standard chihuahuas. Merle chihuahuas are more likely to have hearing and vision problems from birth, these problems do not fix themselves. Because the light pigmentation of a merles  skin, this increases the risk of sunburn and ultraviolet radiation, therefor more likely to get skin cancer.

Merles & The Kennel Club

In June 2010 The British Kennel Club banned the registration of any progeny produced by merle colored Chihuahuas, and stopped recognizing merles Chihuahuas as a pure breed. Kennel Club are seeking to eliminate the merle gene by refusing the breeding of any dogs of that color. No puppies should be Kennel Club registered from a mating of merle sire or dam. However don't be fooled by breeders who sneakily register these puppies under different colors in order to sell them with Kennel Club registrations to gain profits.

Is It Worth The Risk?

Overall if your looking for a chihuahua puppy and you don't want the risk of a deaf, visually impaired Chihuahua or any other merle related illness, your best to stay well clear of a puppy that shows any signs of carrying merle DNA.