SYSTEMATIC IDENTIFICATION OF ESSENTIAL GENES BY IN-VITRO MARINER MUTAGENESIS

Although the complete DNA sequences of several microbial genomes are n ow available, nearly 40% of the putative genes lack identifiable funct ions. Comprehensive screens and selections for identifying functional classes of genes are needed to convert sequence data into meaningful b iological information. One particularly significant group of bacterial genes consists of those that are essential for growth or viability, H ere, ne describe a simple system for performing transposon mutagenesis on naturally transformable organisms along with a technique to rapidl y identify essential or conditionally essential DNA segments,We show t he general utility of this approach by applying it to two human pathog ens, Haemophilus influenzae and Streptococcus pneumoniae, in which we detected known essential genes and assigned essentiality to several OR Fs of unknown function.