Cute features — a little round face or short, tiny legs — are what attract people to their first pet. However, these features that we find cute are often the result of selective breeding that prioritize an animal’s appearance at the cost of its health. While health problems in pets are most commonly associated with selective breeding, cross-breeding, or the mating of different breeds within the same species, can also create disadvantages for pets. Therefore, choosing which type — purebred or mixed breed — to adopt can be a challenge.
The main advantage and purpose of cross-breeding is that it creates new mixed breeds that may be more appealing to look at. However, while people are focused on a pet’s visual appearance, they don’t mention how these alterations are affecting the animal’s communicative and physical abilities.
In a study that focused on cats’ genetic features, it was found that changes in their facial features caused misalignment with associated expressions. Many cats are bred to have “brachycephalic,” or flat-faced features, that consist of a shortened skull, short muzzle and excessive skin. Observations showed that on average, neutral expressions in “brachycephalic” cats correlated with pain-like features found in breeds with medium or longer skulls. Along with that, another abnormality in “brachycephalic” cats is narrower airways, which causes “negative respiratory implications.” Additionally, these problems can be seen in “brachycephalic” dogs.
Dwarfism is another disorder with physical symptoms that some people find adorable. Popular animals exhibiting this trait include corgis and munchkin cats, both of which are selectively bred. However, this abnormal growth disability causes restriction to their movement as well as joint pains.
Yet, the continuation of cross-breeding persists because mixing breeds have shown to eventually eradicate some diseases such as X-linked severe combined immunodeficiency, a mutation found in basset hounds. Since they have a larger gene pool, basset hounds are less prone to develop recessive disorders, despite the possibility of being carriers.
Understanding the concepts of the Mendelian inheritance explains how cross-breeds are actually healthier than purebreds. The chance of a recessive disease increases when the same line of animals with that defect continue to interbreed. Therefore, in cross-breeding, there is a decrease in the chance of inheriting defective genes and carriers when breeds outside of that gene pool are introduced.
A study that tested 24 genetic disorders in purebred and mixed breed dogs showed that genetic disorders were 42% higher in purebreds, 4% higher in mixed dogs and 52% did not have a difference. There were only about three medical anomalies that were higher in mixed breeds.
Although certain mutations are more harmful than others in cats, such as dwarfism, most mixed breeds don’t differ from purebreds. The most common issue cats have is obesity.
Overall, it’s more about personal points of view on this topic. Cross-breeding is beneficial for certain lineage of animals while other combinations might cause more harm than good. The most important thing for potential pet parents is that they are aware of the risks associated with the breed, or breeds, of the animal they plan to adopt and bring home.
Fiona Liu is an Opinion Intern for the winter 2021 quarter. She can be reached at email@example.com