Development of a new tool to improve gene transfer frequency calculations.

Gene transfer frequency can be determined experimentally on plates, but the methods currently in use do not discriminate between independent transfers and clonal multiplication of initial transformants. In order to overcome this bias, we engineered an Acinetobacter baylyi population in which cells differed by a specific molecular signature and used it as recipient in transformation experiments. Our results suggest that a corrective factor of 0.52 should be applied in order to accurately report natural transformation when using the plate counting method.