An in vitro molecular vehicle system for Bacillus subtilis has been developed which will allow the replication and transposition of selected fragments of DNA. Isolated specific fragments of the B. subtilis chromosome will be analyzed genetically to select for sporulation genes. the organization of sporulation genes within the spore loci will be studied. The gene amplification system consists of a host bacterium, B. subtilis; and a molcular vehicle, a temperate Bacillus phage, phi-do-7, genome cleaved once by restriction enzyme Sal GI. Specific fragments of the B. subtilis chromosome have already been isolated using agarose electrophoresis and and restriction enzymes. A large number of these fragments will be characterized by transformation to determine which contain sporulation genes. A search for regulatory genes will include in vitro mutagenesis of fragments containing sporulation genes. Development of this system will provide a powerful tool for B. subtilis, making it even more valuable in areas where it has made landmark contributions. Cloning of sporulation genes will provide a unique approach to the study of bacterial morphogenesis.