Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
School of Mathematics and Statistics, University of Sheffield, Sheffield, UK.
Sci Adv. 2018 Nov 7;4(11):eaau5484. doi: 10.1126/sciadv.aau5484. eCollection 2018 Nov.
Vertebrates have a vast array of epithelial appendages, including scales, feathers, and hair. The developmental patterning of these diverse structures can be theoretically explained by Alan Turing's reaction-diffusion system. However, the role of this system in epithelial appendage patterning of early diverging lineages (compared to tetrapods), such as the cartilaginous fishes, is poorly understood. We investigate patterning of the unique tooth-like skin denticles of sharks, which closely relates to their hydrodynamic and protective functions. We demonstrate through simulation models that a Turing-like mechanism can explain shark denticle patterning and verify this system using gene expression analysis and gene pathway inhibition experiments. This mechanism bears remarkable similarity to avian feather patterning, suggesting deep homology of the system. We propose that a diverse range of vertebrate appendages, from shark denticles to avian feathers and mammalian hair, use this ancient and conserved system, with slight genetic modulation accounting for broad variations in patterning.
脊椎动物有各种各样的上皮附属物，包括鳞片、羽毛和毛发。这些不同结构的发育模式可以用艾伦·图灵的反应扩散系统理论上解释。然而，该系统在早期分化谱系（与四足动物相比）上皮附属物模式形成中的作用，例如软骨鱼类，了解甚少。我们研究了鲨鱼独特的牙齿状皮肤齿状突起的模式形成，这与它们的流体动力学和保护功能密切相关。我们通过模拟模型证明，图灵样机制可以解释鲨鱼齿状突起的模式形成，并通过基因表达分析和基因途径抑制实验验证该系统。该机制与鸟类羽毛的模式形成惊人地相似，表明该系统具有很深的同源性。我们提出，从鲨鱼齿状突到鸟类羽毛和哺乳动物毛发等多种多样的脊椎动物附属物都使用这种古老而保守的系统，只是轻微的遗传调节导致了模式形成的广泛变化。
