Otaki Joji M
The BCPH Unit of Molecular Physiology, Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
BMC Syst Biol. 2012 Mar 13;6:17. doi: 10.1186/1752-0509-6-17.
To explain eyespot colour-pattern determination in butterfly wings, the induction model has been discussed based on colour-pattern analyses of various butterfly eyespots. However, a detailed structural analysis of eyespots that can serve as a foundation for future studies is still lacking. In this study, fundamental structural rules related to butterfly eyespots are proposed, and the induction model is elaborated in terms of the possible dynamics of morphogenic signals involved in the development of eyespots and parafocal elements (PFEs) based on colour-pattern analysis of the nymphalid butterfly Junonia almana.
In a well-developed eyespot, the inner black core ring is much wider than the outer black ring; this is termed the inside-wide rule. It appears that signals are wider near the focus of the eyespot and become narrower as they expand. Although fundamental signal dynamics are likely to be based on a reaction-diffusion mechanism, they were described well mathematically as a type of simple uniformly decelerated motion in which signals associated with the outer and inner black rings of eyespots and PFEs are released at different time points, durations, intervals, and initial velocities into a two-dimensional field of fundamentally uniform or graded resistance; this produces eyespots and PFEs that are diverse in size and structure. The inside-wide rule, eyespot distortion, structural differences between small and large eyespots, and structural changes in eyespots and PFEs in response to physiological treatments were explained well using mathematical simulations. Natural colour patterns and previous experimental findings that are not easily explained by the conventional gradient model were also explained reasonably well by the formal mathematical simulations performed in this study.
In a mode free from speculative molecular interactions, the present study clarifies fundamental structural rules related to butterfly eyespots, delineates a theoretical basis for the induction model, and proposes a mathematically simple mode of long-range signalling that may reflect developmental mechanisms associated with butterfly eyespots.
为了解释蝴蝶翅膀眼斑颜色图案的确定过程，基于对各种蝴蝶眼斑的颜色图案分析，人们讨论了诱导模型。然而，目前仍缺乏能够为未来研究奠定基础的眼斑详细结构分析。在本研究中，我们提出了与蝴蝶眼斑相关的基本结构规则，并基于蛱蝶科蝴蝶苎麻珍蝶的颜色图案分析，从眼斑和副焦点元素（PFE）发育过程中形态发生信号的可能动态角度，对诱导模型进行了详细阐述。
在发育良好的眼斑中，内部黑色核心环比外部黑色环宽得多；这被称为内侧宽规则。似乎信号在眼斑焦点附近较宽，随着它们向外扩展而变窄。尽管基本信号动态可能基于反应扩散机制，但从数学角度可以很好地将其描述为一种简单的均匀减速运动，即与眼斑和PFE的外部和内部黑色环相关的信号在不同的时间点、持续时间、间隔和初始速度下释放到一个基本均匀或渐变阻力的二维场中；这产生了大小和结构各异的眼斑和PFE。通过数学模拟可以很好地解释内侧宽规则、眼斑畸变、大小眼斑之间的结构差异以及眼斑和PFE对生理处理的结构变化。本研究进行的形式化数学模拟也合理地解释了传统梯度模型难以解释的自然颜色图案和先前的实验结果。
在一个没有推测性分子相互作用的模式下，本研究阐明了与蝴蝶眼斑相关的基本结构规则，勾勒出诱导模型的理论基础，并提出了一种数学上简单的远程信号传导模式，该模式可能反映了与蝴蝶眼斑相关的发育机制。
