DISSERTATION RESEARCH: Population genetic structure and the evolution of specialization within a multi-species ant-microbe symbiosis

微生物共生体在塑造生命多样性方面发挥着关键作用，从致病病原体到有益微生物。微生物相互作用的进化动力学在单个物种内或相互作用的物种对之间的理解最好;然而，进一步的多物种研究是必要的，以了解这些动力学如何在更广泛的共生体社区内变化。真菌生长的蚂蚁（Apterostigma dentegerum）是解决这些问题的理想选择，因为它保持多种共生体，包括真菌品种，攻击病原体的品种，以及互惠共生的细菌，其抗生素分泌物对抗感染。初步研究表明，栽培品种并不专门对抗最常见的病原体物种的感染;然而，细菌很可能填补了这一角色。这项研究将产生群体遗传结构数据的A。dentegerum，再加上生物测定实验，试图了解主机/共生体传输和基因流的影响，在一个复杂的多物种共生专业化的演变。 这项研究在一个更复杂的框架内应用了群体遗传学和共同进化理论中的长期概念。由于这项工作直接涉及病原体耐药性的进化动力学和抗生素效力的维持，因此其结果将对健康产生广泛的影响。这项研究将依靠本科生（包括代表性不足的少数民族）的协助，他们将接受各种分子遗传学和微生物学技术的培训。最后，这项研究的结果将被纳入研究人员的微生物生态学和进化课程，除了研究人员参加的年度K-12公共宣传活动。

Microbial symbionts play key roles in shaping the diversity of life, from disease causing pathogens to beneficial microbes. The evolutionary dynamics of microbial interactions are understood best within single species or between pairs of interacting species; however, further multi-species studies are necessary to understand how these dynamics change within a broader community of symbionts. The fungus-growing ant (Apterostigma dentigerum) is ideal for addressing such questions, as it maintains multiple symbionts, including fungal cultivars, cultivar-attacking pathogens, and mutualistic bacteria whose antibiotic secretions combat infection. Preliminary work has shown that cultivars are not specialized to combat infection by their most common pathogen species; however, the bacteria are likely filling this role. This study will generate population genetic structure data for A. dentigerum and, coupled with bioassay experiments, seeks to understand how host/symbiont transmission and gene flow impact the evolution of specialization within a complex multi-species symbiosis. This study applies long-standing concepts in population genetics and coevolutionary theory within a more complex framework. Because the proposed work speaks directly to the evolutionary dynamics of pathogen resistance and the maintenance of antibiotic potency, the results will have broad health implications. This study will rely on the assistance of undergraduates (including underrepresented minorities), who will become trained in a variety of molecular genetic and microbiological techniques. Finally, the results of this study will be incorporated into the researchers' microbial ecology and evolution course, in addition to annual K-12 public outreach events attended by the researchers.