The effect of inbreeding or linebreeding on the immune system
By Sue Thatcher
Shit Tzu breeder
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I decided to write this article after overhearing yet another breeder saying they were proposing to do a half brother/half sister mating "just to see what it produces". One of the things such a close mating will produce is an impaired immune system. Unfortunately you won´t be able to see an impaired immune system nor will you be able to test for it. However your baby puppies will grow up to be more prone to infections and more likely to suffer autoimmune disease (such as Dry Eye) or allergies. The immune system is inherited as a whole, ie the puppy inherits a complete immune system from I s sire and a complete immune system from it´s dam. The more different complete immune systems the puppy has the stronger it´s immune system will be. MHC genes code for proteins that detect pathogens and label infect cells so that the immune system can destroy them. The more diverse the genes at the MHC, the more pathogens can be recognised and hence the stronger the immune function is. Example 1 A puppy from unrelated parents
Example 2 A puppy from related parents (half brother/half sister)
You have impaired the immune system by 25%. This diminishes the body´s capability to mount and effective immune response. Such dogs are more prone to infections and are more likely to suffer autoimmune disease (such as Dry Eye, Thyroiditis, Demodex, Hemolytic Anemia) or allergies. An animal with a diverse immune system can produce a greater variety of proteins and deal with a greater variety of pathogens than an animal with an immune system limited by inbreeding. That´s the individual benefit. Even more significant is the population benefit. In a population with many different immune systems, at least some individuals will be able to mount and effective immune response against almost anything that might come along. Taken from: "The French Connection" FBCofE. Winter 07. UK |
