Jon Perry - Genetics & Evolution Stated Casually | What mutations give dogs flat faces? Evolutionary Question #14 @StatedCasually | Uploaded 4 years ago | Updated 1 day ago
Geneticists have recently discovered the specific mutations that give dogs flat noses. These are found in brachycephilic breeds like Pugs, Apple Head Chihuahuas, Boston Terriers, and French Bulldogs.

Here are the papers:

1. Molecular origins of rapid and continuous morphological evolution
2. Variation of BMP3 Contributes to Dog Breed Skull Diversity
3. Canine Brachycephaly Is Associated with a Retrotransposon-Mediated Missplicing of SMOC2