The long term objectives of this proposal are to understand the process of evolution in asexual microorganisms, and the genetic structure of their populations. Recent work in thsi area has revealed that asexual microorganism populations possess a level of genetic complexity far greater than previously supposed.
The specific aims of this project will be to analyse the factors influencng the evolution of population stucture in the yeast Saccharomyces cerevisiae. We will focus on adaptive mutations arising in long-term laboratory populations. The great majority of the adaptive mutants have already been identified from earlier work, and samples containng them are maintained in storage at -70oC. In particular we plan a) to analyse the role of transposable elements and gross chromosomal rearrangements (including loss) in the generation of thes adaptive mutations, b) determine the fitness interactions between them, c) determine the origins and genealogical relationships of the adaptive mutants to understand how population structure changes an evolves and d) assess the development of genetic polymorphism and environmental complexity in simple laboratory populations where growth is limited initially by a single resource. For the most part we will use well developed and documented microbiological and molecular genetic techniques. As well as being important to population genetics an evolution, these studies will provide important information on the evolution and ageing of proliferating cell populations. The complete understanding of cell proliferation and the genetic changes that the cells undergo is critically important to many aspects of medicine, not the least of which are cancer treatment and ageing.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Genetics Study Section (GEN)
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University of Michigan Ann Arbor
Schools of Arts and Sciences
Ann Arbor
United States
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Treves, D S; Manning, S; Adams, J (1998) Repeated evolution of an acetate-crossfeeding polymorphism in long-term populations of Escherichia coli. Mol Biol Evol 15:789-97
Rosenzweig, R F; Sharp, R R; Treves, D S et al. (1994) Microbial evolution in a simple unstructured environment: genetic differentiation in Escherichia coli. Genetics 137:903-17
Adams, J; Puskas-Rozsa, S; Simlar, J et al. (1992) Adaptation and major chromosomal changes in populations of Saccharomyces cerevisiae. Curr Genet 22:13-9
Wilke, C M; Maimer, E; Adams, J (1992) The population biology and evolutionary significance of Ty elements in Saccharomyces cerevisiae. Genetica 86:155-73
Rosenzweig, R F (1992) Regulation of fitness in yeast overexpressing glycolytic enzymes: parameters of growth and viability. Genet Res 59:35-48
Wilke, C M; Adams, J (1992) Fitness effects of Ty transposition in Saccharomyces cerevisiae. Genetics 131:31-42
Modi, R I; Castilla, L H; Puskas-Rozsa, S et al. (1992) Genetic changes accompanying increased fitness in evolving populations of Escherichia coli. Genetics 130:241-9
Rosenzweig, R F (1992) Regulation of fitness in yeast overexpressing glycolytic enzymes: responses to heat shock and nitrogen starvation. Genet Res 59:167-77
Modi, R I; Wilke, C M; Rosenzweig, R F et al. (1991) Plasmid macro-evolution: selection of deletions during adaptation in a nutrient-limited environment. Genetica 84:195-202
Kurlandzka, A; Rosenzweig, R F; Adams, J (1991) Identification of adaptive changes in an evolving population of Escherichia coli: the role of changes with regulatory and highly pleiotropic effects. Mol Biol Evol 8:261-81

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