Transmission of a Complex or Polygenic
Genetic Disease in Dogs
What is a complex or polygenic genetic disease?
Complex or polygenic genetic diseases are caused by mutations in multiple genes, often in interaction with environmental factors. Unlike monogenic diseases, where a single mutation in one gene is enough to cause the disease, polygenic diseases result from the combined effect of multiple genetic variations.
Key points to better understand this concept:
Multifactorial nature: Polygenic diseases result from the interaction between several genes and the environment. For example, hip dysplasia in dogs is influenced by genes that affect joint development, as well as environmental factors such as nutrition and exercise.
Symptom variability: The symptoms of polygenic diseases can vary greatly depending on the specific combination of genes and environmental influences. For instance, some dogs may show mild symptoms of hip dysplasia, while others may be severely affected.
Concrete example: Hip dysplasia is a common polygenic disease in dogs. If a dog with a genetic predisposition for this condition is bred with another dog with the same predisposition, their puppies will have an increased risk of developing the disease. However, the clinical expression will also depend on environmental factors such as body weight and physical activity.
Implications for breeding: Managing polygenic diseases is more complex than managing monogenic ones. Breeders must not only take into account the results of genetic tests but also environmental management practices to minimize disease risk. For example, to reduce the incidence of hip dysplasia, it is crucial to monitor the nutrition and exercise of puppies, in addition to selecting breeders with good genetic scores.
In summary, Complex or polygenic genetic diseases involve the interaction of multiple genes and environmental factors. This complexity requires an integrated approach to breeding management in order to minimize risks and improve dogs’ health.
Sources :
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Veterinary Genetics Laboratory