One of the most distinctive body parts of your typical English bulldog, French bulldog, or Boston terrier—their coiled screw tail—might be caused by a specific genetic mutation, suggests recent research. And more importantly for us humans, that same genetic quirk might help scientists better understand a rare disorder in people.

Bulldogs and terriers are some of the many breeds known for their scrunched-up, wide heads (formally known as brachycephalic breeds). Cute as this feature might be, though, it actually raises a dog’s risk of serious health problems. For instance, the flattened skulls can restrict their oxygen flow, making them more likely to have breathing or heart issues, and their often bulged-out eyes can be prone to injury. But bulldogs and terriers are even worse off, since most are born with deformed spines. The literal end result of this trait is the shortened screw tail they carry around.

The researchers behind the current study, published last month in PLOS Genetics, wanted to get a closer look at the genetic differences underlying different breeds, particularly screw-tailed dogs.

Read more from Gizmodo