Evolutionäre Grundlagen der Diversität von Alphaproteobacteria

虽然原核生物代表了最多样化的生物群体，但塑造其种群结构的力量的相对重要性仍在争论中。特别是，很少有人知道的机制和动力学的功能分化的天然细菌种群和有关的进化机制。在第一个资助期内，确定了丰富的鞘氨醇单胞菌科的微多样性人口。通过培养回收了95个代表菌株，并通过9个管家基因的分析阐明了它们的群体结构，这揭示了不同亚群的存在。使用这一大组合适的分离株，适应性的过程，潜在的群体亚结构的鞘氨醇单胞菌科现在将阐明和基因组目标的选择确定。因此，计划在第二资助阶段进行的突变、重组和选择的综合分析将基于（i）对来自不同亚群的全基因组序列的测定和比较生物信息学分析，（ii）开发和验证改进的进化模型，以解释观察到的种群多样性，特别是确定当地的（小生境特异性）扫描和同源依赖性重组的参数，（iii）亚群的小生境特异性基因的鉴定，和（iv）亚群的原位特异性表达模式的分析。

While prokaryotes represent the most diverse group of organisms, the relative importance of the forces that shape their population structure are still under debate. In particular, little is known about the mechanisms and dynamics of functional differentiation in natural bacterial populations and about the underlying evolutionary mechanisms. During the first funding period, a microdiverse population of abundant Sphingomonadaceae was identified. 95 representative strains were recovered by cultivation and their population structure elucidated by the analysis of 9 housekeeping genes, which revealed the presence of distinct subpopulations. Using this large set of suitable isolates, the adaptive processes underlying the population substructure of the Sphingomonadaceae will now be elucidated and the genomic targets of selection identified. The comprehensive analysis of mutation, recombination and selection scheduled for the second funding phase will therefore be based on (i) the determination and comparative bioinformatic analysis of full genome sequences from the different subpopulations, (ii) the development and validation of improved evolutionary models to explain the observed population diversity and in particular to determine the rates of local (niche-specific) sweeps and the parameters of homology-dependent recombination, (iii) the identification of niche-specific genes of subpopulations, and (iv) the analysis of specific expression patterns of subpopulations in situ.