The receptors that allow people to perceive the bitter taste of drinks such as hoppy beer and coffee were already present in some fishes 450 million years ago, researchers have found1. Bitter taste receptors help humans and other organisms to recognize potentially toxic compounds so that they can avoid consuming them. Akihiro Itoigawa at Meiji University in Kawasaki, Japan, and his colleagues scoured the DNA of 18 cartilaginous fishes, including sharks, rays and skates, for genes enc...