Squid Euprymna scolopes and Vibrio fischeri symbioses exist in nature as a multi-strain colonization model. Transformation is the process of a cell incorporating exogenous DNA into its genome. In Vibrio fischeri, natural transformation efficiency varies in co-isolated strains. This project uses transformation efficiencies of natural isolates via an erythromycin reporter gene under different protocol conditions to maximize efficiency. This technique can be utilized to generate mutants and explore strain co-evolution.