Lineage-specific loss of function of bitter taste receptor genes in humans and nonhuman primates
Lineage-specific loss of function of bitter taste receptor genes in humans and nonhuman primates
复制标题
DOI：
10.1534/genetics.104.037523
复制
发表时间：
2005-05-01
期刊：
影响因子：
3.3
通讯作者：
Takahata, N
中科院分区：
文献类型：
--
作者：
Go, Y;Satta, Y;Takahata, N
由于成为死亡基因或假基因（假基因化）的过程是不可逆的，并且在某些环境条件下可以相当迅速地发生，因此它是描述物种特异性的一个合理的决定因素。为了验证这一进化假设，我们分析了人类以及12种非人类灵长类动物苦味受体（T2 R）基因的复制和假基因化的克里思和模式。结果表明，灵长类动物比小鼠积累了更多的假基因后，他们从共同的祖先和谱系特异性假基因化变得更加明显，在人类比非人类灵长类动物。虽然积极的选择已经在细胞外结构域中的一些氨基酸上操作，但对T2R基因的功能限制在灵长类动物中比在小鼠中更宽松，并且这种趋势最终导致人类的味觉能力迅速恶化。由于T2R分子在避免一般苦味有毒有害物质中起着重要作用，T2R基因库的实质性修饰可能反映了对环境变化的不同反应，并导致灵长类进化过程中物种特异性食物偏好。
Since the process of becoming dead genes or pseudogenes (pseudogenization) is irreversible and can occur rather rapidly under certain environmental circumstances, it is one plausible determinant for characterizing species specificity. To test this evolutionary hypothesis, we analyzed the tempo and mode of duplication and pseudogenization of bitter taste receptor (T2R) genes in humans as well as in 12 nonhuman primates. The results show that primates have accumulated more pseudogenes than mice after their separation from the common ancestor and that lineage-specific pseudogenization becomes more conspicuous in humans than in nonhuman primates. Although positive selection has operated on some amino acids in extracellular domains, functional constraints against T2R genes are more relaxed in primates than in mice and this trend has culminated in the rapid deterioration of the bitter-tasting capability in humans. Since T2R molecules play an important role in avoiding generally bitter toxic and harmful substances, substantial modification of the T2R gene repertoire is likely to reflect different responses to changes in the environment and to result from species-specific food preference during primate evolution.