A phylogenomic rodent tree reveals the repeated evolution of masseter architectures
A phylogenomic rodent tree reveals the repeated evolution of masseter architectures
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DOI：
10.1098/rspb.2019.0672
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
M. Swanson;C. Oliveros;Jacob A. Esselstyn
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文献类型：
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作者：
M. Swanson;C. Oliveros;Jacob A. Esselstyn
了解一个性状进化的次数是理解其与选择机制、发育限制和进化多样化之间潜在关系的必要基础。啮齿动物占现存哺乳动物物种的40%以上，它们在生态和进化上的成功部分归因于咬合效率的提高，这是由于咬肌的一个或两个部分从颧弓向前移动到喙上。这种向前的转变以三种不连续的方式发生，但它发生的次数从未被明确量化。我们估计了一个超度量的遗传学，第一个包括所有啮齿动物的家庭，使用数千个ultraconserved元素。我们研究了五个啮齿动物亚目之间的进化关系的支持，然后纳入相关的化石，拟合模型的字符进化，并使用随机字符映射，以确定咬肌的一部分已经向前移动到喙上至少七次（一个逆转）在大约70万年的啮齿动物的历史。结合起来，这一关键创新的重复进化，随着时间的推移，它的流行程度越来越高，以及具有这种特征的进化枝的物种多样性，强调了提高叮咬效率的适应价值和一些有利性状出现的相对容易性。
Understanding the number of times a trait has evolved is a necessary foundation for comprehending its potential relationships with selective regimes, developmental constraints and evolutionary diversification. Rodents make up over 40% of extant mammalian species, and their ecological and evolutionary success has been partially attributed to the increase in biting efficiency that resulted from a forward shift of one or two portions of the masseter muscle from the zygomatic arch onto the rostrum. This forward shift has occurred in three discrete ways, but the number of times it has occurred has never been explicitly quantified. We estimated an ultrametric phylogeny, the first to include all rodent families, using thousands of ultraconserved elements. We examined support for evolutionary relationships among the five rodent suborders and then incorporated relevant fossils, fitted models of character evolution, and used stochastic character mapping to determine that a portion of the masseter muscle has moved forward onto the rostrum at least seven times (with one reversal) during the approximately 70 Myr history of rodents. Combined, the repeated evolution of this key innovation, its increasing prevalence through time, and the species diversity of clades with this character underscores the adaptive value of improved biting efficiency and the relative ease with which some advantageous traits arise.