Response to climate warming in a tropical ectotherm: an investigation of epigenetic and mitochondrial haplogroup effects

热带变温带对气候变暖的响应：表观遗传和线粒体单倍群效应的研究

• 批准号: 1656670
• 负责人: Jeanne Zeh
• 金额: $ 80.83万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-15 至 2022-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1656670&HistoricalAwards=false
• 关键词: Response; climate; warming; tropical; ectotherm

A central premise of modern biology has been that inheritance and individual variation are ultimately controlled by the sequence of DNA bases in the genome. However, discoveries in molecular genetics are revealing a more complex reality in which an array of heritable chemical signals determine when, where and in what environmental contexts genes are turned on or turned off. Such control of gene expression is much more sensitive to environmental influences than DNA sequence, and environmentally-induced changes can be transmitted across generations to effect changes in offspring growth, metabolism, neurological development and fertility. A major unresolved question is whether transmission of acquired information across generations enables organisms to respond to environmental challenges or not. This project exploits the unique reproductive characteristics of a model arthropod species, in which embryos develop in an external, transparent brood sac and can be monitored and manipulated, to determine whether environmentally-induced epigenetic effects play a causal role in the transmission of altered gene expression patterns from parents to offspring. The project will provide training for K-12 instructors, high school students, undergraduates, graduate students and a postdoctoral scholar and will include high school outreach in the form of museum exhibits, internships, presentations, training in molecular techniques, advising in science project competitions and assistance with curriculum development. The impact of naturally occurring mitochondrial variation on the epigenetic regulation of nuclear gene expression by small noncoding RNAs (sncRNAs) and its effects on evolutionary responses to environmental challenges are poorly understood. This project will exploit two highly divergent mitochondrial haplogroups (A, B2) that co-occur in populations of the pseudoscorpion, Cordylochernes scorpioides, to determine whether selection acting on this pool of genetic diversity can enable this tropical arthropod to respond to temperature-induced physiological stress through adaptation and/or environmentally-induced epigenetic changes. The project will include: (1) a multi-generation experiment to examine the response of A and B2 haplogroups to incrementally increasing temperatures; (2) an epigenetic response experiment in which replicates of the haplogroups will be reared as split broods at control and elevated temperatures, and offspring assayed from the control and elevated temperature treatment crosses, and (3) a study in which differentially-expressed sncRNAs will be microinjected into early-stage embryos to assess possible causal epigenetic effects on elevated temperature response. Taken together, these experiments will address the potential for an adaptive evolutionary response to environmental challenges, and will determine whether: (1) divergent mitochondrial haplogroups differ in their responses; (2) epigenetic effects are adaptive or pathological; (3) epigenetic effects are transmitted paternally or maternally, and (4) differentially expressed sncRNAs play a causal role in the transmission of environmentally-induced epigenetic modifications.

现代生物学的一个核心前提是，遗传和个体变异最终由基因组中的DNA碱基序列控制。然而，分子遗传学的发现揭示了一个更复杂的现实，即一系列可遗传的化学信号决定了基因在何时、何地以及在何种环境背景下被打开或关闭。 基因表达的这种控制比DNA序列对环境影响更敏感，环境引起的变化可以代代相传，影响后代的生长、代谢、神经发育和生育能力。一个尚未解决的主要问题是，获得的信息跨代传递是否使生物体能够应对环境挑战。该项目利用了一种模式节肢动物物种的独特生殖特征，其中胚胎在外部透明的育囊中发育，可以被监测和操纵，以确定环境诱导的表观遗传效应是否在改变基因表达模式从父母传递到后代中发挥因果作用。该项目将为K-12教师、高中生、本科生、研究生和一名博士后学者提供培训，并将包括以博物馆展览、实习、演示、分子技术培训、科学项目竞赛咨询和课程开发援助等形式开展的高中外联活动。自然发生的线粒体变异对小分子非编码RNA（sncRNA）对核基因表达的表观遗传调控的影响及其对环境挑战的进化反应的影响知之甚少。该项目将利用两个高度不同的线粒体单倍型群（A，B2），共同出现在人口的pseudocorpion，Cordylochernes scorpioides，以确定是否选择作用于这个池的遗传多样性，可以使这个热带节肢动物，以应对温度引起的生理压力，通过适应和/或环境引起的表观遗传变化。该项目将包括：（1）一个多代实验，以检查A和B2单倍型群对逐渐增加的温度的反应;（2）表观遗传反应实验，其中将单倍型群的重复作为分开的窝在对照和升高的温度下饲养，并且对来自对照和升高的温度处理杂交的后代进行分析，以及（3）将差异表达的sncRNA显微注射到早期胚胎中以评估对升高的温度反应的可能的因果表观遗传效应的研究。总之，这些实验将解决适应性进化对环境挑战的反应的潜力，并将确定：（1）不同的线粒体单倍型群在其反应中是否不同;（2）表观遗传效应是适应性的还是病理性的;（3）表观遗传效应通过父系或母系传递，和（4）差异表达的sncRNA在环境诱导的表观遗传修饰的传递中起因果作用。

项目成果

Sperm competitive advantage of a rare mitochondrial haplogroup linked to differential expression of mitochondrial oxidative phosphorylation genes

• DOI: 10.1111/jeb.13536
• 发表时间: 2019-09
• 期刊: Journal of Evolutionary Biology
• 影响因子: 2.1
• 作者: J. A. Zeh;Maya A Zawlodzki;Melvin M. Bonilla;Eleanor Su-Keene;Michael V. Padua;D. W. Zeh

Simulated climate warming and mitochondrial haplogroup modulate testicular small non-coding RNA expression in the neotropical pseudoscorpion, Cordylochernes scorpioides

• DOI: 10.1093/eep/dvy027
• 发表时间: 2018-10
• 期刊: Environmental Epigenetics
• 影响因子: 3.8
• 作者: Eleanor Su-Keene;Melvin M. Bonilla;Michael V. Padua;D. W. Zeh;J. A. Zeh