Bitter taste perception enables the detection of potentially toxic molecules and thus evokes avoidance behavior in vertebrates. It is mediated by bitter taste receptors, TAS2Rs. One of the best-studied TAS2R is TAS2R38. Phenylthiocarbamide (PTC) perception and TAS2R38 receptors vary across primate species, and this variation may be related to variation in dietary preferences. In particular, we previously found that the low sensitivity of TAS2R38s in Asian colobines likely evolved as an adaptation to their leaf-eating behavior. However, it remains unclear whether this low PTC sensitivity is a general characteristic of the subfamily Colobinae, a primate group that feeds predominantly on leaves. We performed genetic analyses, functional assays with mutant proteins, and behavioral analyses to evaluate the general characteristics of TAS2R38 in colobines. We found that PTC sensitivity is lower in TAS2R38s of African colobines than in TAS2R38s of omnivorous macaques. Furthermore, two amino acids shared between Asian and African colobines were responsible for low sensitivity to PTC, suggesting that the last common ancestor of extant colobines had this phenotype. We also detected amino acid differences between TAS2R38s in Asian and African colobines, indicating that they evolved independently after the separation of these groups.

中文翻译：

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Colobine 中苦味受体 TAS2R38 的进化

苦味感知能够检测到潜在的有毒分子，从而激发脊椎动物的回避行为。它由苦味受体 TAS2Rs 介导。研究最多的 TAS2R 之一是 TAS2R38。苯硫脲 (PTC) 感知和 TAS2R38 受体因灵长类动物而异，这种变化可能与饮食偏好的变化有关。特别是，我们之前发现亚洲鲟鱼中 TAS2R38s 的低敏感性可能演变为对它们食叶行为的适应。然而，目前尚不清楚这种低 PTC 敏感性是否是 Colobinae 亚科的一般特征，这是一种主要以叶子为食的灵长类动物。我们对突变蛋白进行了遗传分析、功能分析、和行为分析以评估 colobine 中 TAS2R38 的一般特征。我们发现非洲鲟的 TAS2R38s 的 PTC 敏感性低于杂食性猕猴的 TAS2R38s。此外，亚洲和非洲 colobines 之间共享的两个氨基酸导致对 PTC 的低敏感性，这表明现存 colobines 的最后一个共同祖先具有这种表型。我们还检测到亚洲和非洲 colobine 中 TAS2R38s 之间的氨基酸差异，表明它们在这些群体分离后独立进化。表明现存colobines的最后一个共同祖先具有这种表型。我们还检测到亚洲和非洲 colobine 中 TAS2R38s 之间的氨基酸差异，表明它们在这些群体分离后独立进化。表明现存colobines的最后一个共同祖先具有这种表型。我们还检测到亚洲和非洲 colobine 中 TAS2R38s 之间的氨基酸差异，表明它们在这些群体分离后独立进化。