Comparative Complementation Mapping of Methylophilus spp. Using Cosmid Gene Libraries and Prime Plasmids

1 Department of Genetics, Monash University, Clayton, Victoria 3168, Australia 2 The Galton Laboratory, Department of Genetics and Biometry, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK ABSTRACT SUMMARY: Cosmid gene libraries of the obligate methylotrophs Methylophilus viscogenes and Methylophilus methylotrophus AS1 were generated by ligating Sau 3A partial digests of chromosomal DNA into the broad-host-range cosmid vector pLA2917. Genetic linkage groups were identified for each organism by complementation following mobilization of the recombinant cosmids to a wide range of Pseudomonas aeruginosa and Escherichia coli auxotrophs. The linkage data thus obtained confirmed and extended those previously established by prime plasmid complementation, and the two methylotrophs showed very similar arrangements for four of the gene clusters studied. However, comparison of DNA sequences which complemented the same auxotrophic markers failed to demonstrate restriction fragment identity or substantial DNA-DNA homology between the two methylotrophs.