Frequent Expansions of the Bitter Taste Receptor Gene Repertoire during Evolution of Mammals in the Euarchontoglires Clade
Frequent Expansions of the Bitter Taste Receptor Gene Repertoire during Evolution of Mammals in the Euarchontoglires Clade
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DOI：
10.1093/molbev/msu144
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发表时间：
2014-08-01
影响因子：
10.7
通讯作者：
Go, Yasuhiro
中科院分区：
文献类型：
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作者：
Hayakawa, Takashi;Suzuki-Hashido, Nami;Go, Yasuhiro
哺乳动物的基因组研究对于理解人类的生物学特征，特别是医学模型动物如猕猴和小鼠的研究非常重要。此外，Euarchontoglires基因组的动态生态进化特征可能会被发现，因为该分支中的许多物种的特征是成功地适应辐射到各种生态位。本研究基于39个全基因组序列的同源性搜索，对28种真鲨类苦味受体基因（TAS2Rs）的进化轨迹进行了研究。Euarchontoglires物种拥有可变数量的完整的TAS2Rs，范围从16到40，和他们的最后共同祖先至少有26个完整的TAS2Rs。基因树显示，至少有7个谱系特异性事件涉及大量基因复制。基因复制在类人猿的祖先分支（类人猿集群）中特别明显，这可能促进了类人猿特征的适应性进化，例如嗅觉和其他感官之间的权衡以及草食性特征的发展。随后的全基因缺失的类人猿集群TAS2Rs的类人猿物种表明正在进行的异位同源重组的类人猿集群。这些研究结果提供了深入了解适应性感官进化在各种生态位中的作用，以及与包括人类在内的Euarchontoglires哺乳动物物种的味觉多样性相关的分子机制的重要线索。
Genome studies of mammals in the superorder Euarchontoglires (a clade that comprises the orders Primates, Dermoptera, Scandentia, Rodentia, and Lagomorpha) are important for understanding the biological features of humans, particularly studies of medical model animals such as macaques and mice. Furthermore, the dynamic ecoevolutionary signatures of Euarchontoglires genomes may be discovered because many species in this clade are characterized by their successful adaptive radiation to various ecological niches. In this study, we investigated the evolutionary trajectory of bitter taste receptor genes (TAS2Rs) in 28 Euarchontoglires species based on homology searches of 39 whole-genome assemblies. The Euarchontoglires species possessed variable numbers of intact TAS2Rs, which ranged from 16 to 40, and their last common ancestor had at least 26 intact TAS2Rs. The gene tree showed that there have been at least seven lineage-specific events involving massive gene duplications. Gene duplications were particularly evident in the ancestral branches of anthropoids (the anthropoid cluster), which may have promoted the adaptive evolution of anthropoid characteristics, such as a trade-off between olfaction and other senses and the development of herbivorous characteristics. Subsequent whole-gene deletions of anthropoid cluster TAS2Rs in hominoid species suggest ongoing ectopic homologous recombination in the anthropoid cluster. These findings provide insights into the roles of adaptive sensory evolution in various ecological niches and important clues related to the molecular mechanisms that underlie taste diversity in Euarchontoglires mammalian species, including humans.