TAS2R45 is a bitter taste receptor that functions as a G-protein coupled receptor involved in the detection of bitter chemical stimuli and bitter taste perception 1. The receptor is localized to the plasma membrane and mediates chemosensory detection of bitter compounds. TAS2R45 belongs to a family of 25 human bitter taste receptors with substantial genetic diversity; however, the specific cognate ligand for TAS2R45 remains unidentified despite functional screening against a library of 106 bitter compounds, suggesting it may be highly selective for bitter substances not yet tested 1. The TAS2R45 gene at chromosome 12 exhibits significant copy number variation, with deletion alleles (45Δ) occurring at high global frequency (0.18) across human populations, resulting in individuals carrying 0-2 copies of the functional gene 2. These deletions likely evolved recently through unequal recombination and show African origin without evidence of strong natural selection 2. Clinically, TAS2R45 expression is relevant to mood disorders, with pathway analysis showing downregulated taste transduction genes including TAS2R45 in women with unipolar depression compared to controls and bipolar patients, suggesting potential biomarker utility for depression phenotyping 3.