Comparative genomics reveals convergent evolution between the bamboo-eating giant and red pandas
Comparative genomics reveals convergent evolution between the bamboo-eating giant and red pandas
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比较基因组学揭示食竹巨熊猫和小熊猫之间的趋同进化
DOI：
10.1073/pnas.1613870114
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发表时间：
2017-01-31
影响因子：
11.1
通讯作者：
Wei, Fuwen
中科院分区：
文献类型：
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作者：
Hu, Yibo;Wu, Qi;Wei, Fuwen
意义大熊猫和小熊猫是专性食竹动物，它们独立地从食肉祖先进化而来，并拥有适应性假拇指，使它们成为研究趋同进化的理想模型。在这项研究中，我们确定了与吃竹子相关的趋同进化的基因组特征。比较基因组分析显示，适应性收敛基因可能涉及假拇指的发展和必要的竹子养分利用。我们还发现，鲜味味觉受体基因TAS1R1已假基因在这两个熊猫。这些发现提供了深入了解的遗传机制表型收敛和适应一个专门的竹子饮食在两个大熊猫，并提供了一个例子，基因组规模的分析检测收敛进化。远亲类群之间的表型趋同往往反映了对相似选择压力的适应，并可能受到遗传趋同的驱动。大熊猫（Ailuropoda melanoleuca）和小熊猫（Ailurus fulgens）属于食肉目的不同科，但它们都进化出了专门的竹子饮食和适应性假拇指，代表了经典的趋同进化模型。然而，这些形态和生理收敛的遗传基础仍然未知。通过对小熊猫基因组的从头测序和对大熊猫基因组组装的改进，我们发现了趋同进化的基因组特征。肢体发育基因DYNC2H1和PCNT经历了适应性收敛，可能是假拇指发育的重要候选基因。作为对竹子饮食的进化反应，适应性趋同已经发生在参与竹子营养素（如必需氨基酸、脂肪酸和维生素）消化和利用的基因中。同样，在这两只大熊猫中，鲜味受体基因TAS1R1也被假基因化。这些研究结果提供了深入了解遗传收敛机制的基础表型收敛和适应一个专门的竹子饮食。
Significance The giant panda and red panda are obligate bamboo-feeders that independently evolved from meat-eating ancestors and possess adaptive pseudothumbs, making them ideal models for studying convergent evolution. In this study, we identified genomic signatures of convergent evolution associated with bamboo eating. Comparative genomic analyses revealed adaptively convergent genes potentially involved with pseudothumb development and essential bamboo nutrient utilization. We also found that the umami taste receptor gene TAS1R1 has been pseudogenized in both pandas. These findings provide insights into genetic mechanisms underlying phenotypic convergence and adaptation to a specialized bamboo diet in both pandas and offer an example of genome-scale analyses for detecting convergent evolution. Phenotypic convergence between distantly related taxa often mirrors adaptation to similar selective pressures and may be driven by genetic convergence. The giant panda (Ailuropoda melanoleuca) and red panda (Ailurus fulgens) belong to different families in the order Carnivora, but both have evolved a specialized bamboo diet and adaptive pseudothumb, representing a classic model of convergent evolution. However, the genetic bases of these morphological and physiological convergences remain unknown. Through de novo sequencing the red panda genome and improving the giant panda genome assembly with added data, we identified genomic signatures of convergent evolution. Limb development genes DYNC2H1 and PCNT have undergone adaptive convergence and may be important candidate genes for pseudothumb development. As evolutionary responses to a bamboo diet, adaptive convergence has occurred in genes involved in the digestion and utilization of bamboo nutrients such as essential amino acids, fatty acids, and vitamins. Similarly, the umami taste receptor gene TAS1R1 has been pseudogenized in both pandas. These findings offer insights into genetic convergence mechanisms underlying phenotypic convergence and adaptation to a specialized bamboo diet.