Unraveling the Evolutionary Origins of Umami and Sweet Taste Preferences

Genome-wide survey reveals a high level of diversity in how taste receptors evolved among vertebrates.

A new study led by researchers from Kindai University, Japan, identified five new groups of umami and sweet taste receptors within the TAS1R family (TAS1R 4, 5, 6, 7, and 8) and also diversity in TAS1R2 and TAS1R3 genes. (Credit: Hidenori Nishihara from Kindai University). See larger figure at end.

The perception of taste is one of the most important senses and helps us identify beneficial foods and avoid harmful substances. For instance, our fondness for sweet and savory foods results from our need to consume carbohydrates and proteins. Given their importance as an evolutionary trait, researchers around the world are investigating how taste receptors originated and evolved over a period of time. Obtaining these insights into the feeding behavior of organisms can help the researchers paint a picture of the history of life on Earth. One of the important tastes in our taste palette is umami, or the savory taste, which is associated with proteins that form a vital part of the diets of many organisms. The taste receptor type 1 (T1R) detects sweet and umami tastes among mammals. This taste receptor is encoded by the TAS1R, a family of genes, including TAS1R1, TAS1R2, and TAS1R3, and comes from a common ancestor of bony vertebrates. However, this gene pattern is not observed in coelacanth and cartilaginous fishes, where “taxonomically unplaced” TAS1R genes have been identified, suggesting an incomplete understanding of the evolutionary history of taste receptors. Now, however, a research team led by Associate Professor Hidenori Nishihara from Kindai University, Japan, and Professor Yoshiro Ishimaru from Meiji University, Japan, has identified five new, previously undiscovered groups within the TAS1R family. This discovery is a result of a genome-wide survey of jawed vertebrates including all major fish groups.

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