Evolutionäre Grundlagen der Diversität von Alphaproteobacteria

• Applicant: Professor Dr. Jörg Overmann
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2008 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 64631874

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.

• DFG Programme: Research Units
• Subproject of: FOR 1078: Natural Selection in Structered Populations