Host virus coevolution – demography versus selection in the face of multiple stressors

有一个持续的兴趣，以加快适应性进化的速度，并需要更好地了解影响进化速度的因素。特别是，我们缺乏一个详细的了解如何在基因组水平上的进化动力学与种群的适应度分布在复杂的环境中一起进化。在这里提出的项目中，我们的目标是确定共同进化的宿主病毒群体中的快速适应性基因组变化，并确定宿主和病毒的多种压力源如何改变快速适应的速率和轨迹。在先前的实验中，结合基因组分析，我们展示了宿主的人口变化和宿主与病毒之间的协同进化如何影响宿主和病毒基因组水平上的适应性变化。使用相同的实验系统和生物信息学工具，在以前的项目中开发的，我们现在的目标是测试的假设，非生物压力和物种相互作用交互影响的适应性进化的步伐。我们将在多个水平上跟踪随时间变化的动态，即种群动态，表型和基因组变化以及在表型水平（时移实验）和基因组水平（全基因组关联）详细观察到的数百（840）个藻类克隆的变化。我们将明确测试病毒和/或宿主的额外非生物应激源是否会直接改变共同进化动力学（i）通过改变选择的强度和方向性，（ii）通过不同个体之间的相互作用（克隆干扰），（iii）通过基因组内的相互作用（多效性，上位性），或（iv）间接通过人口统计学变化。总的来说，我们将确定是否以及如何引入非生物压力的环境复杂性限制了抗性进化的步伐，即使突变率很高。

There is a continuing interest to characterise the pace of adaptive evolution and a need for a better understanding of the factors influencing the rate of evolution. Especially, we lack a detailed understanding on how evolutionary dynamics at the genomic level relate to the distribution of fitness in populations evolving together in complex environments. In the project proposed here, we aim to identify rapid adaptive genomic changes in coevolving host-virus populations and to determine how multiple stressors for the host and virus alter the rate and trajectory of rapid adaptation. In previous experiments combined with genomic analyses we showed how demographic changes of host and coevolution between the host and virus affected adaptive changes at the genome level of both, host and virus. Using the same experimental system and the bioinformatics tools developed in the previous project, we now aim testing the hypothesis that abiotic stressors and species interactions interactively affect the pace of adaptive evolution. We will follow the dynamics of changes across time at multiple levels, i.e. population dynamics, phenotypic and genomic changes and characterise observed changes across a few hundred (840) algae clones in detail at the phenotype level (time shift experiments) and at the genome level (genome-wide associations). We will explicitly test if additional abiotic stressors for virus and/or host will alter the coevolutionary dynamics directly (i) through altering the strength and directionality of selection, (ii) through interactions between different individuals (clonal interference), (iii) through interactions within the genome (pleitropy, epistasis), or (iv) indirectly through demographic changes. Overall we will identify if and how environmental complexity introduced by abiotic stressors constrains the pace of resistance evolution even when the mutation rate is high.