Researchers have traced the screw-like tail of bulldogs and some terriers to a genetic variant that is similar to one found in people with Robinow syndrome, Gizmodo reports.
In addition to their squashed faces — which can cause breathing problems — bulldogs, French bulldogs, and Boston terriers also have kinked tails because they don't have the vertebrae that make up the tail bone, the University of California, Davis adds. Researchers led by Davis' Danika Bannasch sequenced the genomes of 100 dogs, including 10 dogs from such screw-tail breeds to tease out the genetic root of this type of tail.
As they reported recently in PLOS Genetics, the researchers found screw-tail dogs have a frameshift mutation in DISHEVELLED 2 (DVL2), which is part of the WNT signaling pathway. This mutation, they add, alters the protein, which affects communication between cells and tissue development.
An analogous mutation, they note, occurs in people with Robinow syndrome, who have craniofacial, limb, and vertebral malformations similar to what's observed in the dogs. "It's a very rare human disease but very common in dogs, so that could be a model for the human syndrome," Bannasch says in a statement.