Animals: The evolution of taste receptors
Humans can sense five basic tastes: sweet, savoury (umami), sour, bitter and salt corresponding to the availability of key nutrients or, in the case of bitterness, toxins. The adaptive value of this ability is clear.
There are two exercises in this Case Study in which students investigate the evolution of taste receptors in a range of animals. In the first activity, protein sequence data is used to generate a phylogenetic tree of sweet, umami and bitter taste receptors from six animal species. In the second, more advanced, activity, the evolution of bitter taste receptors by gene duplication is studied using DNA sequence data.
The unusual case of the giant panda, which has lost the ability to taste meaty flavours, is also introduced.
Case study written by: Anne Fischer, formerly of the Max Planck Institute for Evolutionary Anthropology, Leipzig and Dean Madden, NCBE, University of Reading.