The Role of Core and Variable Gene Regulatory Network Modules in Tooth Development and Evolution
The Role of Core and Variable Gene Regulatory Network Modules in Tooth Development and Evolution
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DOI：
10.1093/icb/icaa116
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发表时间：
2023-07-31
影响因子：
2.6
通讯作者：
Sears，Karen E.
中科院分区：
文献类型：
--
作者：
Sadier，Alexa;Santana，Sharlene E.;Sears，Karen E.
在已提出的影响进化方向的发育过程中，发育基因调控网络(GRN)的模块化组织显示出特别的前景。从理论上讲，GRN有核心模块，包括基本的、保守的基因电路，以及更容易发生变异的下游二级基因电路的子模块。虽然这一想法最近受到了相当大的兴趣，但EVO-DEVO领域缺乏严格评估这一假设所需的实验系统。在这里，我们介绍一个实验系统，脊椎动物的牙齿，它有很大的潜力作为检验这一假说的模型。牙齿发育及其相关的GRN已经在模式生物和非模式生物中得到了很好的研究和模拟。我们认为，牙齿GRN中模块的存在既解释了发育机制的保守，也解释了脊椎动物牙齿的非凡多样性。根据实验数据，我们假设存在一个保守的核心基因模块，它对于确保牙齿或尖牙的启动和发育是绝对必要的。对于物种间的牙齿形态变异，我们认为，在牙齿发育的后期，例如牙齿及其尖端的形态发生期间，激活的更宽松的子模块控制着牙齿形态变异的不同轴。
Among the developmental processes that have been proposed to influence the direction of evolution, the modular organization of developmental gene regulatory networks (GRNs) has shown particular promise. In theory, GRNs have core modules comprised of essential, conserved circuits of genes, and sub-modules of downstream, secondary circuits of genes that are more susceptible to variation. While this idea has received considerable interest as of late, the field of evo-devo lacks the experimental systems needed to rigorously evaluate this hypothesis. Here, we introduce an experimental system, the vertebrate tooth, that has great potential as a model for testing this hypothesis. Tooth development and its associated GRN have been well studied and modeled in both model and non-model organisms. We propose that the existence of modules within the tooth GRN explains both the conservation of developmental mechanisms and the extraordinary diversity of teeth among vertebrates. Based on experimental data, we hypothesize that there is a conserved core module of genes that is absolutely necessary to ensure tooth or cusp initiation and development. In regard to tooth shape variation between species, we suggest that more relaxed sub-modules activated at later steps of tooth development, for example, during the morphogenesis of the tooth and its cusps, control the different axes of tooth morphological variation.