Department of Biology, Indiana University, Bloomington, IN, USA.
INIBIOMA, Universidad Nacional del Comahue - CONICET, Bariloche, Argentina.
Nat Ecol Evol. 2020 Jul;4(7):970-978. doi: 10.1038/s41559-020-1202-x. Epub 2020 May 18.
Nutrition-responsive development is a ubiquitous and highly diversified example of phenotypic plasticity, yet its underlying molecular and developmental mechanisms and modes of evolutionary diversification remain poorly understood. We measured genome-wide transcription in three closely related species of horned beetles exhibiting strikingly diverse degrees of nutrition responsiveness in the development of male weaponry. We show that (1) counts of differentially expressed genes between low- and high-nutritional backgrounds mirror species-specific degrees of morphological nutrition responsiveness; (2) evolutionary exaggeration of morphological responsiveness is underlain by both amplification of ancestral nutrition-responsive gene expression and recruitment of formerly low nutritionally responsive genes; and (3) secondary loss of morphological responsiveness to nutrition coincides with a dramatic reduction in gene expression plasticity. Our results further implicate genetic accommodation of ancestrally high variability of gene expression plasticity in both exaggeration and loss of nutritional plasticity, yet reject a major role of taxon-restricted genes in the developmental regulation and evolution of nutritional plasticity.
营养响应型发育是表型可塑性的一个普遍且高度多样化的例子，但它的潜在分子和发育机制以及进化多样化的模式仍知之甚少。我们测量了三个密切相关的角甲虫物种的全基因组转录水平，这些物种在雄性武器的发育过程中表现出明显不同程度的营养响应。我们表明：（1）在低营养和高营养背景下差异表达基因的数量反映了物种特有的形态营养响应程度；（2）形态响应的进化夸大是由祖先营养响应基因表达的放大和以前低营养响应基因的招募共同作用的；（3）对营养的形态响应的二次丧失与基因表达可塑性的显著降低相一致。我们的研究结果进一步表明，遗传适应祖先高基因表达可塑性的变异性在营养可塑性的夸大和丧失中都起着重要作用，但排除了分类群限制基因在营养可塑性的发育调控和进化中的主要作用。
