Tag archives: double merle

While advancements in science, medicine, and agriculture have played a role in decreasing the relative importance of the dog in human survival, their importance as pets, companions, and surrogate family members may be greater than ever. Once more commonly selected for their athletic prowess and behavioral traits, the rise of dog fancying over the past 250 years has elevated the importance of canine aesthetics to previously unprecedented heights. As a result, dog breeders have historically gone to great lengths to produce dogs with unique phenotypic characteristics desirable to potential pet buyers. While most of these characteristics are simple, mendelian genetic traits without health concerns, some desirable and interesting traits such as the merle coat color pattern are unique to domestic animals and bring with them a complexity and potential health concerns that veterinarians should be aware of in their goal of facilitating canine health and wellbeing. 

An Interesting Mutation for an Interesting Haircoat

In 2006, Dr. Leigh Anne Clark and others identified a semi-dominant genetic mutation responsible for the merle coat color pattern commonly seen in numerous dog breeds including the Australian shepherd, collie, border collie, and dachshund. Merle coat color is marked by areas of normal, eumelanistic pigmentation ...

Paw Print Genetics was approached by the Australian Shepherd Health & Genetics Institute (ASHGI) to conduct a pilot project on blue-eyed, tricolored (BET) Australian shepherds (Aussies) to understand whether these dogs have the SINE insertion in the PMEL gene that can cause a variety of coat color and pattern variations known as merle.  Identifying whether these dogs do or do not have the merle mutation can help inform how to conduct a larger research study.  The merle mutation seemed a logical place to start, as dogs with classic merle coat color patterns can have blue eyes [Clark et al., 2006].

With the help of ASHGI and several breeder volunteers, we collected 38 BET dogs that have blue eyes but no coat variations associated with carrying a copy of the merle mutation. These dogs were not randomly selected from the whole Aussie population, but rather, were sent to us from the breeder volunteers. Thus, many of the dogs collected may have been related.

Paw Print Genetics recently launched a high-resolution test for merle that allows for identifying variation within the SINE insertion and allows for discrimination of the various possible merle alleles. Using this DNA sequence-based, high-resolution test, we ...

At Paw Print Genetics we are passionate about prevention of inherited diseases of dogs. Through modern technologies, there are over 150 inherited diseases that can now be prevented through genetic testing of breeding dams and sires. Through use of the information gained from testing, informed decisions can be made for choosing breeding pairs to avoid producing pups afflicted with certain inherited diseases. Unfortunately however, not everyone that currently breeds dogs is aware of genetic testing availability or the importance of these genetic technologies in the overall well-being of their favorite breed. As a result, thousands of dogs are born every year with diseases that can now be prevented.

While the ability to prevent inherited diseases brings happy thoughts, the outcomes of dogs bred without the use of genetic technologies can be much less joyous. Historically, many dogs born with inherited disease were either euthanized or died due to complications of their condition. However, Paw Print Genetics was recently invited to visit a sanctuary for dogs called Double J Dog Ranch, where dogs with special needs find compassion, training, and eventually their forever home, through adoptions to families prepared for the unique opportunity of owning a special needs dog. Many of ...