Data from: Cellular basis of morphological variation and temperature-related plasticity in Drosophila melanogaster strains with divergent wing shapes

Organ shape evolves through cross-generational changes in developmental patterns at cellular and/or tissue levels that ultimately alter tissue dimensions and final adult proportions. Here, we investigated the cellular basis of an artificially selected divergence in the outline shape of Drosophila melanogaster wings, by comparing flies with elongated or rounded wing shapes but with remarkably similar wing sizes. We also tested whether cellular plasticity in response to developmental temperature was altered by such selection. Results show that variation in cellular traits is associated with wing shape differences, and that cell number may play an important role in wing shape response to selection. Regarding the effects of developmental temperature, a size-related plastic response was observed, in that flies reared at 16 °C developed larger wings with larger and more numerous cells across all intervein regions relative to flies reared at 25 °C. Nevertheless, no conclusive indication of altered phenotypic plasticity was found between selection strains for any wing or cellular trait. We also described how cell area is distributed across different intervein regions. It follows that cell area tends to decrease along the anterior wing compartment and increase along the posterior one. Remarkably, such pattern was observed not only in the selected strains but also in the natural baseline population, suggesting that it might be canalized during development and was not altered by the intense program of artificial selection for divergent wing shapes.

器官形态的演化源于细胞及/或组织层面发育模式的跨代改变，此类改变最终会重塑组织尺寸与成体最终比例。本研究以黑腹果蝇（Drosophila melanogaster）为对象，通过比较翅形细长或圆润但翅尺寸极为相近的果蝇品系，探究了人工选择导致其翅轮廓形态分化的细胞基础。同时，本研究还检验了此类人工选择是否改变了果蝇对发育温度的细胞可塑性。

研究结果显示，细胞性状的变异与翅形差异显著相关，且细胞数量可能在翅形对人工选择的响应中发挥重要作用。关于发育温度的影响，本研究观察到与尺寸相关的可塑性响应：相较于25℃条件下饲养的果蝇，16℃饲养的果蝇所发育出的翅膀更大，且所有翅脉间区的细胞体积更大、数量更多。尽管如此，在不同选择品系间，未发现任何翅相关性状或细胞性状的表型可塑性发生显著改变的确凿证据。

本研究同时描述了细胞面积在不同翅脉间区的分布规律：细胞面积沿翅前区逐渐减小，而沿翅后区逐渐增大。值得注意的是，该分布规律不仅在人工选择品系中存在，在自然基线种群中同样可见，这表明翅细胞面积的分布模式可能在发育过程中已被渠化稳定，并未因针对翅形分化的高强度人工选择而发生改变。