Conrad Istock - US grants

Our earlier laboratory studies demonstrated that a natural form of genetic transformation rapidly creates an extensive field of recombinant variation in soil populations of Bacillus subtilis. Studies in this proposal will examine additional aspects of genetic exchange by both transformation and transduction in Bacillus species populations, including: (1) patterns of variation within and between species in nature; (2) a test for the primacy of clonal versus recombining processes in natural populations at B. subtilis including a study at the dynamics of genetic change through time; (3) the effectiveness at transduction in mediating gene exchange in soil; and (4) the extent to which species of Bacillus are or are not closed genetic systems incorporating coadapted genetic systems. The association of Bacillus species in nature will also be studied as background for laboratory experiments involvving transformation across species boundaries. Health-related aspects of this research include the possibility that disease-causing and harmless species in the genus Bacillus may be capabble at exchanging genes and plasmids. In the near future, genetically engineered gene configurations in Bacillus, and other bacterial species, may also be released, intentionally or inadvertently, into nature. The research proposed will help us to plan better field testing of genetically engineered microbes, and to understand how likely it is that products of genetic engineering would circulate within natural populations and pass among species.

During the last four years the Department of Ecology and Evolutionary Biology has successfully sought to attract new faculty members who are active researchers in several developing areas of molecular evolution. In addition, a number of new and established researchers are increasingly beginning to molecular techniques t answer evolutionary questions. Collaborations with researchers in other departments such as Molecular and Cellular Biology and Biochemistry are also increasing. These trends are expected accelerate in the future resulting in even greater interest in utilizing the most modern techniques which are applicable to evolutionary research in a broad range of areas. The renovation and equipping of laboratories to meet these new research needs has involved major capital expenditure which has largely been met through departmental set.up funds for new faculty members and equipment purchased on the grants of individual investigators. However, one major item of equipment, a preparative ultracentrifuge, is still not available in the department. This equipment is currently being borrowed from members of the Departments of Molecular and Cell Biology and Biochemistry and Veterinary Science (located in another building). This is an increasing unsatisfactory arrangement for all concerned. There are serious problems of availability and scheduling and the goodwill of colleagues in other departments is being taxed. An ultracentrifuge for the shared use of members of the Department of Ecology and Evolutionary Biology is therefore an urgent necessity.

Studies of diversification at the level of populations of bacteria in the genus Bacillus are proposed. These analyses will differentiate among alternative models for population genetic structure, models of evolution, and the genetic and phenotypic distinctness of bacterial species in the genus. The central focus is on the evolutionary interplay of clonality and genetic recombination via exchange of genes among cells, clones and species in Bacillus. The question of how cosmopolitan the species are, i.e., the same everywhere genetically and phenotypically, is also a key aspect of the research. Are the species truly global? A great advantage of the proposed research is that direct experimentation with genetic exchange between populations is possible. The studies will involve Bacillus from three ecologically divergent geographical areas: Sonoran Desert, high-altitude Rocky Mountains, and tropical lowland rainforest. Such investigations will inform us about the processes and consequences of evolution in a group of bacteria which have populated the earth since the surface soils and waters became oxygenated about 2 billion years ago, and about evolutionary mechanisms which continue at present among these organisms in both altered and unaltered environments.