Humans love dogs, but petting them can leave some people sneezing and wheezing. About 15% of the world's population lives with a dog allergy, which can increase the risk of hay fever and asthma. The main culprit is Can f 1, a protein found mainly in dog saliva.
Source: [Phys.org](https://phys.org/news/2026-08-gene-beagles-major-dog-allergen.html)