[Genetic and heteroduplex analysis of deletion mutants of plasmid pAS8]

Heteroduplex analysis of deletion mutants of plasmid pAS8 permitted to construct a physical map and to elaborate in greater detail the genetic map of RP4 plasmid. The correlation between the ability of mutants to replicate in cells lacking functional DNA-polymerase I and the length of the deleted segment permitted to map rep genes of RP4 on DNA region with coordinates 9.8-17.3 kb. A relationship between the manifestation of incompatibility of mutants with IncP-1 plasmids and the length of deletions indicates that inc genes(s) are located on DNA region with coordinates 2.1-9.8 kb. The analysis of replication of deletion mutants and the manifestation of incompatibility just as of the data about the size of appropriate deletions permitted to make the conclusion about the functional and genetic non-identity of the replication control and incompatibility control in RP4 plasmid. Different degrees of incompatibility manifested by different plasmids suggest a possible polygenic control of the incompatibility.