MDR1 Breeding Guidelines
This chart provides guidelines for consideration when owners are contemplating breeding dogs that may be affected by the MDR1 mutation. While it is ideal to use only "Normal/Normal" breeding pairs, one must always consider other genetic factors in addition to the MDR1 gene. Because the MDR1 gene is present in such a large percentage of Collies and Australian Shepherds, it may be necessary to breed "Normal/Mutant" dogs in order to maintain a large enough pool of good breeding stock. By using thoughtful breeding strategies including these guidelines, future generations of dogs will have a substantial decrease in the frequency of the mutant MDR1 gene.
MDR1 Breeding Pair Combinations and Outcomes
|Normal/Normal Male||Normal/Mutant* Male||Mutant/Mutant Male|
|Normal/Normal Female||100% Normal/Normal puppies||Normal/Normal and/or Normal/Mutant puppies||100% Normal/Mutant puppies|
|Normal/Mutant* Female||Normal/Normal and/or Normal Mutant puppies||Any combination of puppies||Normal/Mutant and/or Mutant/Mutant puppies|
|Mutant/Mutant Female||100% Normal/Mutant puppies||Normal/Mutant and/or Mutant/Mutant puppies||100% Mutant/Mutant puppies|
*Normal/mutant is the same as mutant/normal and "heterozygote"