Data from: Disintegrating the fly: a mutational perspective on phenotypic integration and covariation

The structure of environmentally induced phenotypic covariation can influence the effective strength and magnitude of natural selection. Yet our understanding of the factors that contribute to and influence the evolutionary lability of such covariation is poor. Most studies have either examined environmental variation without accounting for covariation, or examined phenotypic and genetic covariation without distinguishing the environmental component. In this study we examined the effect of mutational perturbations on different properties of environmental covariation, as well as mean shape. We use strains of Drosophila melanogaster bearing well-characterized mutations known to influence wing shape, as well as naturally-derived strains, all reared under carefully-controlled conditions and with the same genetic background. We find that mean shape changes more freely than the covariance structure, and that different properties of the covariance matrix change independently from each other. The perturbations affect matrix orientation more than they affect matrix eccentricity or total variance. Yet, mutational effects on matrix orientation do not cluster according to the developmental pathway that they target. These results suggest that it might be useful to consider a more general concept of ‘decanalization’, involving all aspects of variation and covariation.

环境诱导表型协变（environmentally induced phenotypic covariation）的结构能够影响自然选择的有效强度与作用幅度。然而，目前学界对这类协变的进化不稳定性（evolutionary lability）的影响因素与促成机制的认知仍较为匮乏。绝大多数相关研究要么仅考察环境变异却未纳入协变关系分析，要么仅探究表型与遗传协变却未区分其中的环境组分。
本研究探究了诱变扰动（mutational perturbations）对环境诱导表型协变的各项特征以及平均表型形状的影响。我们使用了两类黑腹果蝇（Drosophila melanogaster）品系：一类是携带已被充分表征、且已知会影响翅形的诱变突变的品系，另一类为自然来源品系；所有品系均在严格可控的环境条件下饲养，且具备一致的遗传背景。
研究结果显示，平均表型形状相较于协变结构具有更高的演化灵活性；且协方差矩阵（covariance matrix）的各项特征彼此独立地发生变化。相较于对矩阵离心率与总方差的影响，诱变扰动对协方差矩阵取向的改变更为显著。然而，诱变扰动对矩阵取向的影响并未按照其所靶向的发育通路进行聚类。
上述研究结果提示，引入涵盖变异与协变所有维度的‘脱渠化（decanalization）’这一更普适的概念，或具有重要的理论价值。