An Investigation of the Evolution of Autotrophic Endosymbioses in Bivalves By Comparative Molecular Phylogenetic Analysis of Host and Symbiont rRNA Sequences

通过宿主和共生体 rRNA 序列的比较分子系统发育分析研究双壳类自养内共生体的进化

• 批准号: 9420051
• 负责人: Daniel Distel
• 金额: $ 15万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9420051&HistoricalAwards=false
• 关键词: Investigation; Evolution; Autotrophic; Endosymbioses; Bivalves

9420051 DISTEL Symbiotic associations between animals and bacteria are extremely diverse and commonplace in nature. In fact, it is difficult to find examples of animal species whose existence is not profoundly influenced by symbiotic associations with bacteria. For example, mitochondria (the structures within human cells that generate the energy for metabolic processes) are thought to have arisen from ancient bacteria that long ago formed a symbiotic association with the ancestor of all living animals. The support provided for this project will allow investigation of a type of symbiosis commonly found in clams and worms from deep-sea hydrothermal vents (marine hot springs) that can be used as a model system for studying the questions of how bacterial symbioses become established and what role they may play in the creation of new animal and bacterial species. This will be accomplished by comparing the primary DNA sequence (genetic code) of genes which are found in both symbionts and hosts. Computer analysis will be used to generate family trees demonstrating the relationships among symbionts and hosts. Comparison of the branching patterns of host and symbiont trees should reveal the point(s) in the lineages these hosts and symbionts first became associated and what impact their association has had on the diversification of the partner species. This understanding will lay the historical and conceptual foundation upon which future studies of the physiology and ecology of animal bacterial associations will be built. %%% Symbiotic associations ranging from enteric bacteria in the human gut to nitrogen fixing bacteria associated with plant roots or luminous light organs in deep-sea fish provide a broad range of benefits to their hosts. Consequently, symbioses between bacteria and animals are critically important to our ecosystems, agriculture and health. This study will provide an experimental model system to address major questions about how bacterial/host symbioses came to exist and wha t role they have played in the history of life on earth. ***

9420051 DISTEL动物和细菌之间的共生关系在自然界中是极其多样和常见的。 事实上，很难找到动物物种的存在不受与细菌共生关系的深刻影响的例子。 例如，线粒体（人类细胞内为代谢过程产生能量的结构）被认为是起源于古老的细菌，很久以前与所有活着的动物的祖先形成了共生关系。 为这一项目提供的支助将使人们能够调查深海热液喷口（海洋温泉）的蛤和蠕虫中常见的一种共生现象，这种共生现象可用作研究细菌共生现象如何形成以及它们在创造新的动物和细菌物种方面可能发挥何种作用的模型系统。 这将通过比较在共生体和宿主中发现的基因的主要DNA序列（遗传密码）来实现。 计算机分析将用于生成家谱，展示共生体和宿主之间的关系。 宿主和共生体树的分支模式的比较应该揭示这些宿主和共生体首先成为关联的谱系中的点，以及它们的关联对伙伴物种的多样化产生了什么影响。 这一认识将奠定历史和概念基础，在此基础上，未来的研究生理学和生态学的动物细菌协会将建立。 从人类肠道中的肠道细菌到与植物根部或深海鱼类发光器官相关的固氮细菌，共生关系为其宿主提供了广泛的益处。 因此，细菌和动物之间的共生关系对我们的生态系统、农业和健康至关重要。 这项研究将提供一个实验模型系统，以解决有关细菌/宿主共生体如何存在以及它们在地球生命史上扮演什么角色的主要问题。 ***