What’s the most popular dog breed in America?
For over three decades, the Labrador retriever enjoyed the top spot, until 2022 when it was dethroned by the French bulldog. Unfortunately, flat-faced breeds like the French bulldog also tend to suffer from brachycephalic obstructive airway syndrome (BOAS), a breathing disorder that can cause a host of health problems—and even death.
Somewhat paradoxically, despite the incidence and awareness of BOAS surging, these dogs have become more popular, both in the United States and in the United Kingdom. Researchers have termed this disconnect the “brachycephalic crisis,” and a new study published today in PLOS One is pointing to a way out.
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Geneticists from the Royal Kennel Club studying BOAS scored bulldogs, French bulldogs, and pugs on traits associated with BOAS like respiratory function, nostril size, and body weight, and estimated their heritability, or how much of the variation is due to genetic factors. They found that 21 to 49 percent of respiratory function was heritable and 31 to 39 percent of nostril size was heritable. Additionally, these traits tend to travel together (along with body weight), making them prime targets for artificial selection.
Put simply, within the confines of these breeds, there’s some genetic wiggle room to work with to relieve BOAS in future generations.
“Our findings provide clear evidence that respiratory health in these breeds is influenced by genetic differences between dogs, and importantly, that improvement is achievable through selective breeding,” study author Joanna Ilska explained in a statement. “By using objective tools like the Respiratory Function Grading Scheme, breeders can make more informed decisions that prioritize health, helping to reduce the prevalence of BOAS over time.”
Of course, the incidence of BOAS is just one half of the equation of the brachycephalic crisis, the other is the rising demand for brachycephalic dogs. So why are we so attracted to these beleaguered, smush-faced canines in the first place? The short answer is that they’re cute. The long answer is that we find them cute in part because they have certain characteristics of human babies. Taken together, their short muzzles, tall foreheads, and relatively large eyes mimic the general appearance of infants, which we’re evolutionarily programmed to find adorable.
While we may not be able to escape our genetic predilection for adorable dogs, we can still work to change their genetic tendency to develop BOAS. After all, we bred them into this predicament, maybe we can breed them out of it, too. 
Lead image: Tanya / Adobe
