Drosophila wing modularity revisited through a quantitative genetic approach

To predict the response of complex morphological structures to selection it is necessary to know how the covariation among its different parts is organized. Two key features of covariation are modularity and integration. The Drosophila wing is currently considered a fully integrated structure. Here, we study the patterns of integration of the Drosophila wing and test the hypothesis of the wing being divided into two modules along the proximo-distal axis, as suggested by developmental, biomechanical, and evolutionary evidence. To achieve these goals we perform a multilevel analysis of covariation combining the techniques of geometric morphometrics and quantitative genetics. Our results indicate that the Drosophila wing is indeed organized into two main modules, the wing base and the wing blade. The patterns of integration and modularity were highly concordant at the phenotypic, genetic, environmental, and developmental levels. Besides, we found that modularity at the developmental level ...若要预测复杂形态结构对自然选择的响应，亟需明晰其各组分间的协变（covariation）组织模式。协变的两大核心特征为模块化（modularity）与整合性（integration）。目前，果蝇翅被认为是完全整合的结构。本研究聚焦果蝇翅的整合模式，并基于发育学、生物力学及进化生物学证据，验证该翅沿近-远轴分为两个模块的假说。为达成上述研究目标，我们结合几何形态测量学（geometric morphometrics）与数量遗传学（quantitative genetics）技术，开展了多水平协变分析。研究结果表明，果蝇翅确实可划分为两大核心模块：翅基（wing base）与翅叶（wing blade）。整合性与模块化的模式在表型、遗传、环境及发育层面均呈现高度一致性。此外，我们还发现发育层面的模块化……