在一类芥菜中，基因组大小的进化与气候季节性和硫代葡萄糖苷有关，但与生活史、土壤养分或分布范围无关。
Genome size evolution is associated with climate seasonality and glucosinolates, but not life history, soil nutrients or range size, across a clade of mustards.
机构信息
Instituto de Biología, Universidad Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria, Mexico City, Mexico.
Center for Population Biology, University of California, One Shields Avenue, Davis, CA, USA.
出版信息
Ann Bot. 2021 Jun 24;127(7):887-902. doi: 10.1093/aob/mcab028.
BACKGROUND AND AIMS
We investigate patterns of evolution of genome size across a morphologically and ecologically diverse clade of Brassicaceae, in relation to ecological and life history traits. While numerous hypotheses have been put forward regarding autecological and environmental factors that could favour small vs. large genomes, a challenge in understanding genome size evolution in plants is that many hypothesized selective agents are intercorrelated.
METHODS
We contribute genome size estimates for 47 species of Streptanthus Nutt. and close relatives, and take advantage of many data collections for this group to assemble data on climate, life history, soil affinity and composition, geographic range and plant secondary chemistry to identify simultaneous correlates of variation in genome size in an evolutionary framework. We assess models of evolution across clades and use phylogenetically informed analyses as well as model selection and information criteria approaches to identify variables that can best explain genome size variation in this clade.
KEY RESULTS
We find differences in genome size and heterogeneity in its rate of evolution across subclades of Streptanthus and close relatives. We show that clade-wide genome size is positively associated with climate seasonality and glucosinolate compounds. Model selection and information criteria approaches identify a best model that includes temperature seasonality and fraction of aliphatic glucosinolates, suggesting a possible role for genome size in climatic adaptation or a role for biotic interactions in shaping the evolution of genome size. We find no evidence supporting hypotheses of life history, range size or soil nutrients as forces shaping genome size in this system.
CONCLUSIONS
Our findings suggest climate seasonality and biotic interactions as potential forces shaping the evolution of genome size and highlight the importance of evaluating multiple factors in the context of phylogeny to understand the effect of possible selective agents on genome size.
背景与目的
我们研究了形态和生态多样的芸薹科（Brassicaceae）中一个分支的基因组大小的进化模式，以探讨生态和生活史特征与基因组大小之间的关系。虽然已经提出了许多关于有利于小基因组或大基因组的自生和环境因素的假说，但理解植物基因组大小进化的一个挑战是，许多假设的选择因素是相互关联的。
方法
我们为 47 种 Streptanthus Nutt. 及其近缘种提供了基因组大小估计值，并利用该组的许多数据集来收集气候、生活史、土壤亲和性和组成、地理范围和植物次生化学物质的数据，以在进化框架内确定基因组大小变化的同时相关因素。我们评估了各分支的进化模型，并利用系统发育信息分析以及模型选择和信息标准方法，以确定能够最好地解释该分支基因组大小变化的变量。
主要结果
我们发现 Streptanthus 和近缘种的亚分支之间存在基因组大小的差异和进化速率的异质性。我们表明，全分支的基因组大小与气候季节性和硫代葡萄糖苷化合物呈正相关。模型选择和信息标准方法确定了一个最佳模型，该模型包含温度季节性和脂肪硫代葡萄糖苷的分数，这表明基因组大小可能在气候适应中发挥作用，或者生物相互作用在塑造基因组大小进化中发挥作用。我们没有发现支持生活史、范围大小或土壤养分假说作为塑造该系统基因组大小的力量的证据。
结论
我们的研究结果表明，气候季节性和生物相互作用可能是塑造基因组大小进化的潜在力量，并强调了在系统发育背景下评估多个因素以了解可能的选择因素对基因组大小的影响的重要性。
Zotero 插件