Dietary specialization drives multiple independent losses and gains in the bitter taste gene repertoire of Laurasiatherian Mammals.
Dietary specialization drives multiple independent losses and gains in the bitter taste gene repertoire of Laurasiatherian Mammals.
复制标题
饮食专业化导致劳亚兽类哺乳动物苦味基因库中多个独立的损失和增益
DOI：
10.1186/s12983-016-0161-1
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发表时间：
2016
影响因子：
2.8
通讯作者：
Li M
中科院分区：
文献类型：
--
作者：
Liu Z;Liu G;Hailer F;Orozco-terWengel P;Tan X;Tian J;Yan Z;Zhang B;Li M
苦味感知对于有选择性食物摄入的物种来说是必不可少的，使它们能够避免不美味或有毒的食物。先前的研究指出，在不同的脊椎动物物种中，tas2rgenes的数量存在显著差异，但其根本原因尚不清楚。月牙纲哺乳动物具有高度多样化的饮食生态位，在多个谱系中显示出专门的摄食偏好的反复进化，这为研究各种摄食生态位与苦味受体基因拷贝数变化之间的关系提供了独特的机会。结果研究了41种月蝉类动物全基因组序列中tas2rs的进化轨迹及其对苦味感知的影响。完整的as2rs拷贝数变化很大，从0到52个不等。作为狭窄饮食生态位的极端例子，中国穿山甲在所研究的陆生脊椎动物中拥有最少的完整as2rs （n= 2）。海洋哺乳动物（鲸目动物和鳍目动物）整体吞食猎物，tas2rs拷贝数减少（n= 0-5）。相比之下，独立食虫谱系如鼩鼱和食虫蝙蝠具有更高的tas2r多样性（n= 52和n= 20-32），超过草食动物（n= 9-22）和杂食动物（n= 18-22）。结论除草食动物外，食虫动物的tas2rs功能位点比食肉动物和杂食动物多。此外，吞下整个食物的动物（鲸目动物、鳖目动物和穿山甲动物）失去了大部分功能性tas2rs。这些发现提供了迄今为止最全面的关于月牙纲哺乳动物苦味基因库的观点，为哺乳动物tas2rs的损失和获得与饮食专业化之间的关系提供了新的视角。
BackgroundBitter taste perception is essential for species with selective food intake, enabling them to avoid unpalatable or toxic items. Previous studies noted a marked variation in the number ofTAS2Rgenes among various vertebrate species, but the underlying causes are not well understood. Laurasiatherian mammals have highly diversified dietary niche, showing repeated evolution of specialized feeding preferences in multiple lineages and offering a unique chance to investigate how various feeding niches are associated with copy number variation for bitter taste receptor genes.ResultsHere we investigated the evolutionary trajectories ofTAS2Rs and their implications on bitter taste perception in whole-genome assemblies of 41 Laurasiatherian species. The number of intactTAS2Rs copies varied considerably, ranging from 0 to 52. As an extreme example of a narrow dietary niche, the Chinese pangolin possessed the lowest number of intactTAS2Rs (n= 2) among studied terrestrial vertebrates. Marine mammals (cetacea and pinnipedia), which swallow prey whole, presented a reduced copy number ofTAS2Rs (n= 0-5). In contrast, independent insectivorous lineages, such as the shrew and insectivorous bats possessed a higherTAS2Rdiversity (n= 52 andn= 20-32, respectively), exceeding that in herbivores (n= 9-22) and omnivores (n= 18-22).ConclusionsBesides herbivores, insectivores in Laurasiatheria tend to have more functionalTAS2Rs in comparison to carnivores and omnivores. Furthermore, animals swallowing food whole (cetacean, pinnipedia and pangolin) have lost most functionalTAS2Rs. These findings provide the most comprehensive view of the bitter taste gene repertoire in Laurasiatherian mammals to date, casting new light on the relationship between losses and gains ofTAS2Rs and dietary specialization in mammals.