Data from: Morphological novelty emerges from pre-existing phenotypic plasticity

Plasticity-first evolution (PFE) posits that novel features arise when selection refines pre-existing phenotypic plasticity into an adaptive phenotype. However, PFE is controversial because few tests have been conducted in natural populations. Here we present evidence that PFE fostered the origin of an evolutionary novelty that allowed certain amphibians to invade a new niche—a distinctive carnivore morph. We compared morphology, gene expression and growth of three species of spadefoot toad tadpoles when reared on alternative diets: Scaphiopus holbrookii, which (like most frogs) never produce carnivores; Spea multiplicata, which sometimes produce carnivores, but only through diet-induced plasticity; and Spea bombifrons, which often produce carnivores regardless of diet. Consistent with PFE, we found diet-induced plasticity—in morphology and gene expression—in Sc. holbrookii, adaptive refinement of this plasticity in Sp. multiplicata, and further refinement of the carnivore phenotype in Sp. bombifrons. Generally, phenotypic plasticity might play a significant, if underappreciated, role in evolutionary innovation.先可塑性进化（Plasticity-first evolution, PFE）理论提出，当自然选择将预先存在的表型可塑性（phenotypic plasticity）优化为适应性表型时，便会催生进化新奇特征。然而，该理论颇具争议，因目前针对自然种群的验证研究寥寥无几。本研究提供证据表明，PFE推动了一种进化新奇特征的起源——该特征使部分两栖动物得以开拓全新生态位，即独特的食肉型态。我们针对三种锄足蟾蝌蚪开展了不同饮食条件下的形态、基因表达（gene expression）与生长对比实验：其一为Scaphiopus holbrookii，与多数蛙类一致，无法产生食肉型个体；其二为Spea multiplicata，偶尔可产生食肉型个体，但仅能通过饮食诱导的表型可塑性实现；其三为Spea bombifrons，通常无论饮食条件如何均可产生食肉型个体。实验结果与PFE理论相符：我们在Scaphiopus holbrookii中观察到了饮食诱导的形态与基因表达可塑性，在Spea multiplicata中发现了该可塑性的适应性优化，而Spea bombifrons的食肉型态则得到了进一步优化。总体而言，表型可塑性或许在进化创新中发挥了重要作用，即便其贡献尚未被充分认知。