Reductive evolution in three domains of life

Liudmila Yafremava, Crop Sciences, University of Illinois at Urbana-Champaign

Genome reduction is the process by which a genome shrinks relative to its evolutionary ancestor. In the present project we study the global processes of reductive evolution relevant to all three domains of life: Archaea, Bacteria and Eukarya. We investigate how organisms utilize protein architectures, such as folds and fold superfamilies. Results suggest that life originated in a community of complex organisms using a large variety of protein architectures. Over time the architectures were differentially lost by organisms as speciation occurred (reductive evolution). Specifically, Archaea use a limited set of folds stable in the extreme environments, competitive Bacteria have broader but species-specific repertoires of folds, and Eukarya possess the richest repertoires. We hypothesize that the distinct patterns of architecture loss reflect the strategies for architecture usage developed by organisms under the influence of primordial environment.