Abstract DBI 9750072 Joseph E. Peters This action funds an NSF/Alfred P. Sloan Postdoctoral Research Fellowship in Molecular Evolution for 1997. These fellowships support studies involving the theoretical, comparative, computational, and/or experimental analyses of biological patterns and processes at the molecular level within the framework of organismic evolutionary change and adaptation. These studies also include the use of molecular data to address broader evolutionary questions. Each fellowship supports a research and training plan to be carried out in a sponsoring laboratory. The research and training plan for this fellowship is entitled "Dissecting specific interactions between mobile DNA elements to understand bacterial evolution." Mobile DNA elements such as transposons and plasmids increase genetic diversity in bacterial populations. The molecular mechanism by which the bacterial transposon Tn7 specifically targets its insertion into plasmids able to move between cells is being determined. Understanding how mobile DNA elements recognize and interact with each other will provide important insights into how genetic information is rapidly spread through bacterial populations.