Evolution of diversity

多样性的演变

• 批准号: 216921-2008
• 负责人: Doebeli, Michael
• 金额: $ 3.23万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=514162
• 关键词: Evolution; diversity

The origin of diversity is the mystery of mysteries according to Darwin. Millions of species exist today, but the detailed mechanisms generating this diversity are still unclear. The traditional model of speciation is based on geographical isolation: if subpopulations of an ancestral lineage become geographically subdivided (e.g. through fragmentation due to climatic changes), they embark on different evolutionary trajectories, and hence diversify. Here the initial process of splitting the gene pool is not adaptive. In contrast, in the process of adaptive speciation, the splitting of the gene pool is itself an adaptation. The past decade has seen growing interest in such adaptive diversification, because both empirical and theoretical studies have documented its feasibility. The paradigmatic theory of evolutionary branching has popularized the notion that diversification can be driven by ecological interactions such as competition for resources. Using the bacterium E. coli, I have developed a microbial model system to test the theory of adaptive diversification due to evolutionary branching. E. coli offers many advantages, including the possibility of evolving it for thousands of generations and creating a fossil record by freezing intermediate stages. Our evolving E. coli populations have undergone diversification due to competition for carbon resources. Based on molecular, physiological and ecological experiments, my research aims at fully analyzing all aspects of the process of adaptive diversification in this model system, documenting the evolutionary changes prior, during and after the diversification event. We are also studying the origins of diversity in a different microbial system, in which diversification occurs in the context of the general problem of cooperation, leading to coexistence of cooperators and cheaters in the production of a beneficial substance. Another main focus of our research is the mathematical modeling of our experimental model systems based on "reaction kinetics" of individuals, describing individual growth, reproduction and survival using the knowledge gained from our experiments. Finally, we plan to investigate how predation affects diversification in both the experimental and the mathematical model systems.

根据达尔文的说法，多样性的起源是奥秘中的奥秘。如今存在数百万个物种，但产生这种多样性的详细机制仍不清楚。传统的物种形成模型基于地理隔离：如果祖先谱系的亚群在地理上细分（例如，由于气候变化而分裂），它们就会走上不同的进化轨迹，从而多样化。这里，分裂基因库的初始过程是不自适应的。相反，在适应性物种形成过程中，基因库的分裂本身就是一种适应。过去十年，人们对这种适应性多样化的兴趣日益浓厚，因为实证和理论研究都证明了其可行性。进化分支的范式理论普及了这样一种观念，即多样化可以由生态相互作用（例如资源竞争）驱动。我使用大肠杆菌开发了一个微生物模型系统来测试由于进化分支而产生的适应性多样化理论。大肠杆菌具有许多优势，包括可以进化数千代，并通过冻结中间阶段创造化石记录。由于对碳资源的竞争，我们不断进化的大肠杆菌种群已经多样化。我的研究基于分子、生理和生态实验，旨在全面分析该模型系统适应性多样化过程的各个方面，记录多样化事件之前、期间和之后的进化变化。我们还在研究不同微生物系统中多样性的起源，其中多样化是在合作的普遍问题的背景下发生的，导致在有益物质的生产中合作者和作弊者共存。我们研究的另一个主要重点是基于个体的“反应动力学”对我们的实验模型系统进行数学建模，利用从我们的实验中获得的知识来描述个体的生长、繁殖和生存。最后，我们计划研究捕食如何影响实验和数学模型系统的多样化。