From Wolf to Pug: What Sequence Variation Tells Us About the Evolution of Smell Dogs are widely considered to have an excellent sense of smell, which is much more sensitive than that of humans. Since their domestication from grey wolves over 15,000 years ago, almost 400 breeds of dog have developed over time, with different abilities and traits, including sense of smell. Certain breeds have a strong reputation for their keen nose, whilst others are perceived to be less skilled in Despite general assumptions based on their characteristics and the visual distinction between scent hounds and brachycephalic dogs, studies that have compared olfaction between different dog breeds have revealed some inconsistent results. In training-free olfactory tests, scent hounds and hand this area. Behavioural traits and anatomical features may account for some of these differences, but dog breeds also differ in their olfactory receptor genes. This article will summarise key findings from a recent article (Inoue et al. 20251) that used whole-genome data sets from hundreds of dogs across many breeds, to investigate differences in the number of functional genes and variants for three chemosensory receptor gene families – olfactory receptors (ORs), vomeronasal receptors type 1 (V1Rs), and bitter taste receptors (T2Rs).