Potts Abigail S, Hunter Mark D
Department of Ecology & Evolutionary Biology University of Michigan Ann Arbor MI USA.
Ecol Evol. 2021 Jun 8;11(13):8542-8561. doi: 10.1002/ece3.7639. eCollection 2021 Jul.
Phenotypic variability results from interactions between genotype and environment and is a major driver of ecological and evolutionary interactions. Measuring the relative contributions of genetic variation, the environment, and their interaction to phenotypic variation remains a fundamental goal of evolutionary ecology.In this study, we assess the question: How do genetic variation and local environmental conditions interact to influence phenotype within a single population? We explored this question using seed from a single population of common milkweed, , in northern Michigan. We first measured resistance and resistance traits of 14 maternal lines in two common garden experiments (field and greenhouse) to detect genetic variation within the population. We carried out a reciprocal transplant experiment with three of these maternal lines to assess effects of local environment on phenotype. Finally, we compared the phenotypic traits measured in our experiments with the phenotypic traits of the naturally growing maternal genets to be able to compare relative effect of genetic and environmental variation on naturally occurring phenotypic variation. We measured defoliation levels, arthropod abundances, foliar cardenolide concentrations, foliar latex exudation, foliar carbon and nitrogen concentrations, and plant growth.We found a striking lack of correlation in trait expression of the maternal lines between the common gardens, or between the common gardens and the naturally growing maternal genets, suggesting that environment plays a larger role in phenotypic trait variation of this population. We found evidence of significant genotype-by-environment interactions for all traits except foliar concentrations of nitrogen and cardenolide. Milkweed resistance to chewing herbivores was associated more strongly with the growing environment. We observed no variation in foliar cardenolide concentrations among maternal lines but did observe variation among maternal lines in foliar latex exudation.Overall, our data reveal powerful genotype-by-environment interactions on the expression of most resistance traits in milkweed.
表型变异性源于基因型与环境之间的相互作用，是生态和进化相互作用的主要驱动力。衡量遗传变异、环境及其相互作用对表型变异的相对贡献仍然是进化生态学的一个基本目标。在本研究中，我们评估了以下问题：遗传变异和当地环境条件如何相互作用以影响单一物种种群内的表型？我们使用密歇根州北部单一普通马利筋种群的种子来探究这个问题。我们首先在两个常见园圃实验（田间和温室）中测量了14个母系的抗性和抗性性状，以检测种群内的遗传变异。我们对其中三个母系进行了 reciprocal transplant 实验，以评估当地环境对表型的影响。最后，我们将实验中测量的表型性状与自然生长的母本植株的表型性状进行比较，以便能够比较遗传和环境变异对自然发生的表型变异的相对影响。我们测量了落叶水平、节肢动物丰度、叶强心甾内酯浓度、叶乳胶渗出、叶碳和氮浓度以及植物生长情况。我们发现，在常见园圃之间，或者在常见园圃与自然生长的母本植株之间，母系的性状表达缺乏显著相关性，这表明环境在该种群的表型性状变异中起更大作用。除了叶氮和强心甾内酯浓度外，我们发现所有性状都存在显著的基因型与环境相互作用的证据。马利筋对咀嚼式食草动物的抗性与生长环境的关联更为紧密。我们在母系之间未观察到叶强心甾内酯浓度的变化，但确实观察到了母系之间叶乳胶渗出的变化。总体而言，我们的数据揭示了基因型与环境在马利筋大多数抗性性状表达上的强大相互作用。
