show Abstracthide Abstract<b><i>Bacillus atrophaeus</i> 1942</b>. This project will compare modern type strains (e.g. ATCC 9372), strains currently in use within the biodefense community to archival strains of <i>B. atrophaeus</i> to trace the microevolution of <i>B. atrophaeus</i> during more than 70 years of development and use. In addition, this project compares <i>B. atrophaeus</i> subsp. globigii strains to the more distantly related <i>B. atrophaeus</i> subsp. atrophaeus strains.