Modularity of gene expression and tradeoffs in the evolution of plasticity

基因表达的模块化和可塑性进化中的权衡

• 批准号: 7555948
• 负责人: Emilie Snell-Rood
• 金额: $ 4.72万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7555948
• 关键词: Antibiotic Resistance; Architecture; Behavior; Biological Models; Brain; Costs and Benefits; Development; Diabetes Mellitus; Environment; Evolution; Gene Expression; Genes; Genetic; Genetic Drift; Health; Home environment; Horns; Human; Human body; Insecta; Invaded; Learning; Microarray Analysis; Morphology; Mutation; Nutritional; Obesity; Order Coleoptera; Organism; Pattern; Pharmaceutical Preparations; Phenotype; Play; Public Health; RNA Interference; Research; Role; Specificity; Testing; Time; Variant; Virulence; Work; aging brain; coping; cost; developmental genetics; experience; gene function; knock-down; nutrition; pathogen; pleiotropism; tool; trait

DESCRIPTION (provided by applicant): Plasticity in gene expression underlies much of the ability of organisms to cope with environmental variation. Understanding limits in the ability of organisms to adjust to a range of environments has implications for understanding how pathogens respond to human environments (e.g., antibiotic resistance), and how humans respond, at times inappropriately, to current environments (e.g., obesity). This research tests the hypothesis that the degree of modularity, or environmental specificity, of gene expression has fundamental implications for defining limits in the evolution of plasticity. Highly modular gene expression is assumed to permit adaptation to specific environments because overlap in gene function, and thus pleiotropy, is much reduced. At the same time, highly modular gene expression comes at a potential cost: when alternative environments are experienced infrequently, selection on environment-specific genes is weakened and mutation accumulation can occur. These hypotheses will be tested in a newly emerging model system in evolutionary developmental genetics: homed beetles in the genus Onthophagus. These insects display highly divergent alternative phenotypes depending on larval nutrition. Such alternative morphs develop through expression of genes shared across the development of traits, as well as genes specific to different morphs. This research tests several predictions by contrasting the development of secondary sexual traits (horns) and brains in horned (aggressive fighter) and hornless (non-aggressive sneaker) beetle morphs. This research tests four predictions both within and between species: 1) increased environmentally-specific gene expression will be correlated with the evolution of greater ranges of plasticity, 2) genes specific to the development of morph behavior and morphology will be more genetically variable than those shared between morphs, 3) genes specific to morph development experience higher rates of genetic divergence as a result of weak selection, and 4) morph-specific genes will play functional roles in generating divergence between morphs. This work will use a variety of tools developed for Onthophagus beetles, including transcriptional profiling via microarray analysis, and investigating gene function through RNA interference gene knock-down. Relevance. Understanding evolutionary limits of plasticity in gene expression has implications for public health. If we can curb the ability of pathogens to cope with multiple environments, such as invading the human body or dealing with multiple medications, we may be able to reduce pathogen virulence. We may learn why humans cannot express genes that promote health in a wide range of environments, such as diabetes-inducing nutritional environments or changes in the aging brain.

描述（由申请人提供）：基因表达的可塑性是生物体应对环境变化的能力的基础。了解生物体适应一系列环境的能力的限制对于了解病原体如何响应人类环境（例如抗生素耐药性）以及人类如何有时不恰当地响应当前环境（例如肥胖）具有重要意义。这项研究检验了这样的假设：基因表达的模块化程度或环境特异性对于定义可塑性进化的限制具有根本意义。高度模块化的基因表达被认为允许适应特定的环境，因为基因功能的重叠以及因此的多效性大大减少。与此同时，高度模块化的基因表达也有潜在的代价：当很少经历替代环境时，对环境特异性基因的选择就会减弱，并且可能会发生突变积累。这些假设将在进化发育遗传学中新兴的模型系统中进行测试：食甲虫属的家养甲虫。这些昆虫根据幼虫的营养表现出高度不同的替代表型。这种替代变体是通过表达在性状发育过程中共享的基因以及不同变体特有的基因而发展起来的。这项研究通过对比有角（攻击性战斗机）和无角（非攻击性运动鞋）甲虫变形中第二性征（角）和大脑的发育来测试多项预测。这项研究测试了物种内部和物种之间的四个预测：1）增加的环境特异性基因表达将与更大范围的可塑性的进化相关，2）特定于形态行为和形态发展的基因将比形态之间共享的基因更具遗传变异性，3）特定于形态发展的基因由于弱选择而经历更高的遗传分化率，4）形态特异性基因将在 变形之间产生分歧。这项工作将使用为食甲虫开发的各种工具，包括通过微阵列分析进行转录分析，以及通过 RNA 干扰基因敲低来研究基因功能。关联。了解基因表达可塑性的进化限制对公共健康具有重要意义。如果我们能够抑制病原体应对多种环境的能力，例如侵入人体或处理多种药物，我们也许能够降低病原体的毒力。我们可能会了解到为什么人类无法在多种环境中表达促进健康的基因，例如诱发糖尿病的营养环境或衰老大脑的变化。