Cranial modularity shifts during mammalian evolution
Cranial modularity shifts during mammalian evolution
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DOI：
10.1086/505758
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发表时间：
2006-08-01
影响因子：
2.9
通讯作者：
Goswami, Anjali
中科院分区：
文献类型：
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作者：
Goswami, Anjali
几十年来，人们一直将哺乳动物头骨作为几个独立的功能部件进行研究，但对模块化的研究是一种较新的综合方法，旨在对高度相关特征或模块的独立子集进行定量研究。虽然模块化的大多数研究集中在发育和遗传系统，表型模块已经注意到许多不同的形态结构。然而，很少有研究提供在更高的分类水平上比较模块的经验数据，限制了评估模块化更广泛的进化意义的能力。本研究利用18 - 32个三维颅骨标记分析了106种哺乳动物的表型模块性，并证明了颅骨模块性在兽类哺乳动物（有袋类和胎盘类）的进化中普遍保守，但在兽类和单孔目哺乳动物（两个现存的哺乳动物亚类）之间存在差异。聚类分析确定了兽类中6个不同的模块，但只有3个模块在所有物种中显示出显著的整合。单孔显示器只显示两个高度集成的模块。对颅骨功能和发育影响的具体假设进行了测试。骨骼的理论相关矩阵是建立在共享功能、组织起源或骨化模式的基础上的，这三种模型都与观察到的哺乳动物头盖骨相关矩阵显著相关。
The mammalian skull has been studied as several separate functional components for decades, but the study of modularity is a more recent, integrative approach toward quantitative examination of independent subsets of highly correlated traits, or modules. Although most studies of modularity focus on developmental and genetic systems, phenotypic modules have been noted in many diverse morphological structures. However, few studies have provided empirical data for comparing modules across higher taxonomic levels, limiting the ability to assess the broader evolutionary significance of modularity. This study uses 18 - 32 three- dimensional cranial landmarks to analyze phenotypic modularity in 106 mammalian species and demonstrates that cranial modularity is generally conserved in the evolution of therian mammals ( marsupials and placentals) but differs between therians and monotremes, the two extant subclasses of Mammalia. Within therians, cluster analyses identify six distinct modules, but only three modules display significant integration in all species. Monotremes display only two highly integrated modules. Specific hypotheses of functional and developmental influences on cranial bones were tested. Theoretical correlation matrices for bones were constructed on the basis of shared function, tissue origin, or mode of ossification, and all three of these models are significantly correlated with observed correlation matrices for the mammalian cranium.