Global diversity in the TAS2R38 bitter taste receptor: revisiting a classic evolutionary PROPosal
Global diversity in the TAS2R38 bitter taste receptor: revisiting a classic evolutionary PROPosal
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DOI：
10.1038/srep25506
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发表时间：
2016-05-03
影响因子：
4.6
通讯作者：
Drayna, Dennis
中科院分区：
文献类型：
--
作者：
Risso, Davide S.;Mezzavilla, Massimo;Drayna, Dennis
品尝苯硫脲（PTC）和6-正丙基硫氧嘧啶（PROP）的能力是由TAS 2 R38苦味受体基因介导的多态性性状。长期以来，人们一直假设这个基因座的全球遗传多样性是在平衡自然选择的普遍压力下进化的。然而，最近对TAS 2 R的高分辨率群体遗传学研究表明，人口统计学事件在这些基因的进化中发挥了关键作用。我们在这里利用最大的TAS 2 R38数据库进行了分析，包括来自105个群体的5,589个个体，以研究自然选择，单倍型频率和连锁不平衡，以估计选择和人口统计学对该位点当代变异模式的影响。我们发现了一个古老的平衡选择作用于这个基因的迹象，但没有后非洲偏离中性，这意味着目前观察到的变异模式可以主要由人口统计学解释，而不是选择性事件。此外，我们发现了作用于不同非洲TAS 2 R38单倍型的古代选择力的签名。总的来说，我们的研究结果提供了证据，放宽最近的选择力作用于这个基因和修改后的假设，为当今世界范围内分布的TAS 2 R38单倍型的起源。
The ability to taste phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) is a polymorphic trait mediated by the TAS2R38 bitter taste receptor gene. It has long been hypothesized that global genetic diversity at this locus evolved under pervasive pressures from balancing natural selection. However, recent high-resolution population genetic studies of TAS2Rs suggest that demographic events have played a critical role in the evolution of these genes. We here utilized the largest TAS2R38 database yet analyzed, consisting of 5,589 individuals from 105 populations, to examine natural selection, haplotype frequencies and linkage disequilibrium to estimate the effects of both selection and demography on contemporary patterns of variation at this locus. We found signs of an ancient balancing selection acting on this gene but no post Out-Of-Africa departures from neutrality, implying that the current observed patterns of variation can be predominantly explained by demographic, rather than selective events. In addition, we found signatures of ancient selective forces acting on different African TAS2R38 haplotypes. Collectively our results provide evidence for a relaxation of recent selective forces acting on this gene and a revised hypothesis for the origins of the present-day worldwide distribution of TAS2R38 haplotypes.