Bitter taste evolution

Evolution of bitter taste receptors

The sensation of bitterness evolved in the common ancestor of jawed vertebrates: the bitter taste receptor gene family TAS2R is limited to jaw vertebrates, a group that originated about 500 million years ago. The TAS2R gene cluster in tetrapods is massive compared to those in fishes, with great variation from species to species indicating a rich history of evolution. In tetrapods, TAS2R detect toxins, mostly of a plant origin, as a bitter taste.

From Wikipedia, under CC BY-SA. More on occurri.