title: Non-random distribution of macromolecules as driving forces for phenotypic variation.
abstract: Clonal populations employ many strategies of diversification to deal with constraints. All these strategies result in the generation of different phenotypes with diverse functions. Events like cell division are major sources of phenotypic variability due to the unequal partitioning of cellular components. In this review we concentrate on passive and active mechanisms cells employ to distribute macromolecules between their offspring. Different types of segregation are described, addressing both metabolically pertinent molecules such as PHA/PHB or polyphosphates, and components that adversely affect cells by promoting aging, such as damaged protein complexes or extrachromosomal rDNA circles. We also refer to mechanisms generating plasmid copy number (PCN) variation between cells in a population, and how elaborate partitioning systems counteract partitioning errors and ensure equal distribution. Finally, we demonstrate how simple differences in chromosomal copy number determine the fate of a cell, in this case the effect of gene dosage on the onset of sporulation in Bacillus subtilis or on a functional trait in Sinorhizobium meliloti.
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Department Environmental Microbiology, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Jahn
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Department Environmental Microbiology, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Günther
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Department Environmental Microbiology, Permoserstr. 15, 04318 Leipzig, Germany. Electronic address: susann.mueller@ufz.de.
authors.forename: Susann
authors.initials: S
authors.lastname: Müller
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000502:physiology; D001419:Bacteria / Q000235:genetics*; D018407:Bacterial Physiological Phenomena; D002455:Cell Division / Q000235:genetics; D002876:Chromosomes, Bacterial / Q000235:genetics; D018628:Gene Dosage; D016680:Genome, Bacterial; D046911:Macromolecular Substances / Q000378:metabolism*; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D011122:Polyphosphates / Q000378:metabolism; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000502:physiology; D013171:Spores, Bacterial / Q000502:physiology
chemical_list: D046911:Macromolecular Substances; D011122:Polyphosphates