Genetic mapping in Methylophilus methylotrophus AS1.

Prime plasmids have been isolated from Methylophilus methylotrophus AS1 using the IncP-1 plasmid pMO172. Such plasmids can complement mutant function when transferred to appropriate strains of Pseudomonas aeruginosa PAO. From the range of particular functions complemented by each prime plasmid, a preliminary map of the M. methylotrophus AS1 genome with four groups of linked markers was obtained. Physical examination of two of these prime plasmids showed that each had acquired an additional DNA segment. Southern hybridization experiments showed there was sequence homology between the additional DNA segments and M. methylotrophus AS1 DNA, confirming that these prime plasmids carried a segment of the M. methylotrophus AS1 genome. Mapping by complementation may be applicable to other bacteria in which mutants suitable for selecting recombinants are not readily available.