Abstract：
Static allometry is a major component of morphological variation. Much of the literature on the development of allometry investigates how functional perturbations of diverse pathways affect the relationship between trait size and body size. Often, this is done with the explicit objective to identify developmental mechanisms that enable the sensing of organ size and the regulation of relative growth. However, changes in relative trait size can also be brought about by a range of other distinctly different developmental processes, such as changes in patterning or tissue folding, yet standard univariate biometric approaches are usually unable to distinguish among alternative explanations. Here, we utilize geometric morphometrics to investigate the degree to which functional genetic manipulations known to affect the size of dung beetle horns also recapitulate the effect of horn shape allometry. We reasoned that the knockdown phenotypes of pathways governing relative growth should closely resemble shape variation induced by natural allometric variation. In contrast, we predicted that if genes primarily affect alternative developmental processes, knockdown effects should align poorly with shape allometry. We find that the knockdown effects of several genes (e.g., doublesex, Foxo) indeed closely aligned with shape allometry, indicating that their corresponding pathways may indeed function primarily in the regulation of relative trait growth. In contrast, other knockdown effects (e.g., Distal-less, dachs) failed to align with allometry, implicating these pathways in potentially scaling-independent processes. Our findings moderate the interpretation of studies focusing on trait length and highlight the usefulness of multivariate approaches to study allometry and phenotypic plasticity.
摘要：
静态异速是形态变异的主要组成部分。关于异速生长的许多文献都研究了不同途径的功能扰动如何影响性状大小与体型之间的关系。通常,这样做的明确目标是确定能够感知器官大小和调节相对生长的发育机制。然而,相对性状大小的变化也可以由一系列其他明显不同的发育过程引起，例如图案或组织折叠的变化，然而，标准的单变量生物识别方法通常无法区分替代解释。这里,我们利用几何形态计量学来研究已知影响粪甲虫角大小的功能基因操作也概括了角形状测速的影响程度。我们认为，控制相对生长的途径的敲低表型应与自然异速变异引起的形状变异非常相似。相比之下,我们预测，如果基因主要影响替代发育过程，击倒效果应与异速异形配合度差。我们发现几个基因的敲低效应(例如，doublesex,Foxo）确实与形状异速，表明它们相应的途径确实可能主要在相对性状生长的调节中起作用。相比之下,其他击倒效果(例如，无远端,dachs)未能与测速对准，将这些途径牵涉到潜在的不依赖于缩放的过程中。我们的发现缓和了对关注性状长度的研究的解释，并强调了多变量方法研究异速和表型可塑性的有用性。
