Divergent vertebral formulae shape the evolution of axial complexity in mammals.
Divergent vertebral formulae shape the evolution of axial complexity in mammals.
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DOI：
10.1038/s41559-023-01982-5
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发表时间：
2023-03
影响因子：
16.8
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中科院分区：
文献类型：
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复杂性，定义为部分的数量和它们的分化程度，是宏观进化动力学的一个很少探索的方面。毫无疑问，随着进化时间的推移，生物体的最大解剖复杂性已经增加。然而，目前尚不清楚这种增加是否是一个纯粹的扩散过程，或者它是否至少部分地被驱动，在大多数或许多谱系中平行发生，并与最小值和平均值的增加同时发生。高度分化和连续重复的结构，如椎骨，是研究这些模式的有用系统。我们专注于1,136个现存哺乳动物物种的脊柱的序列分化，使用两个指数，量化复杂性的数字丰富度和比例分布的椎骨在骶前区域和第三个表示胸椎和腰椎之间的比例。我们回答三个问题。首先，我们问的复杂性值的分布在主要的哺乳动物群体是相似的，或者分支是否有特定的签名与他们的生态。其次，我们要问的是，在整个进化过程中，复杂性的变化是否偏向于增加，以及是否有证据表明存在驱动趋势。第三，我们要问的是，复杂性的演化变化是否偏离了均匀布朗运动模型。脊椎计数，但不是复杂性指数，显着不同的主要群体之间，并表现出更大的组内变化比迄今为止认识到的。我们发现了强有力的证据表明，一个趋向于增加复杂性，其中更高的值传播进一步增加后代血统。据推断，有几次增长与重大的生态或环境变化相吻合。我们发现支持多速率模型的进化的所有复杂性指标，表明复杂性的增加发生在逐步转变，最近的快速分化的广泛发作的证据。不同的亚支进化出更复杂的脊柱在不同的配置，可能在不同的选择压力和约束，广泛的收敛相同的公式。因此，进一步的工作应侧重于复杂性差异的生态相关性，并更详细地了解历史模式。作者关注1,136种现存哺乳动物的骶前柱序列分化，发现了组内高度变异和复杂性增加的进化趋势的证据。
Complexity, defined as the number of parts and their degree of differentiation, is a poorly explored aspect of macroevolutionary dynamics. The maximum anatomical complexity of organisms has undoubtedly increased through evolutionary time. However, it is unclear whether this increase is a purely diffusive process or whether it is at least partly driven, occurring in parallel in most or many lineages and with increases in the minima as well as the means. Highly differentiated and serially repeated structures, such as vertebrae, are useful systems with which to investigate these patterns. We focus on the serial differentiation of the vertebral column in 1,136 extant mammal species, using two indices that quantify complexity as the numerical richness and proportional distribution of vertebrae across presacral regions and a third expressing the ratio between thoracic and lumbar vertebrae. We address three questions. First, we ask whether the distribution of complexity values in major mammal groups is similar or whether clades have specific signatures associated with their ecology. Second, we ask whether changes in complexity throughout the phylogeny are biased towards increases and whether there is evidence of driven trends. Third, we ask whether evolutionary shifts in complexity depart from a uniform Brownian motion model. Vertebral counts, but not complexity indices, differ significantly between major groups and exhibit greater within-group variation than recognized hitherto. We find strong evidence of a trend towards increasing complexity, where higher values propagate further increases in descendant lineages. Several increases are inferred to have coincided with major ecological or environmental shifts. We find support for multiple-rate models of evolution for all complexity metrics, suggesting that increases in complexity occurred in stepwise shifts, with evidence for widespread episodes of recent rapid divergence. Different subclades evolve more complex vertebral columns in different configurations and probably under different selective pressures and constraints, with widespread convergence on the same formulae. Further work should therefore focus on the ecological relevance of differences in complexity and a more detailed understanding of historical patterns. Focusing on the serial differentiation of the presacral column across 1,136 extant mammal species, the authors find evidence of high within-group variation and an evolutionary trend towards increasing complexity.
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DOI：
10.1073/pnas.0709378105
发表时间：
2008-03-25
影响因子：
11.1
作者：
Adamowicz, Sarah J.;Purvis, Andy;Wills, Matthew A.
通讯作者：
Wills, Matthew A.
影响因子：
3.3
作者：
Eastman, Jonathan M.;Alfaro, Michael E.;Harmon, Luke J.
通讯作者：
Harmon, Luke J.
影响因子：
6.6
作者：
Bapst, David W.
通讯作者：
Bapst, David W.
影响因子：
4.6
作者：
Cavin L;Piuz A;Ferrante C;Guinot G
通讯作者：
Guinot G
影响因子：
6.5
作者：
Bokma, Folmer;Godinot, Marc;Laurin, Michel
通讯作者：
Laurin, Michel