Yingcan Li

Conflicts of Interest The authors declare no conflicts of interest. Supporting Information Filename Description inz270074-sup-0001-DatasetS1.fasta170.7 KB Dataset S1 Intact sequences of Tas1r2 and Tas1r3 identified or analyzed in this study. inz270074-sup-0002-FigureS1.pdf525.6 KB Figure S1 Inactivating mutations in mammalian Tas1r2 and Tas1r3. The first or shared inactivating mutations are highlighted in red. Names of marine mammals are shown in bold.

1 Introduction Sensory systems enable organisms to detect and respond to their surrounding environments, playing a vital role in survival and adaptation (Bachmanov and Beauchamp 2007; Breslin 2013; Liang et al. 2022). Among these systems, taste is a key sense that governs feeding behavior. It is widely accepted that mammals could typically perceive five basic taste modalities: umami, sweet, bitter, salty, and sour (Yarmolinsky et al. 2009; Trivedi 2012).

Sweet taste is a crucial chemosensory modality for detecting natural sugar compounds, which are primarily derived from angiosperms. In vertebrates, excluding birds, sweet taste is typically mediated by the Tas1r2–Tas1r3 heterodimer, and the receptor function often reflects dietary adaptations to sugar-rich diets.