Phylogenetic analysis of tnpR. genes in mercury resistant soil bacteria: the relationship between DNA sequencing and RFLP typing approaches

Abstract The diversity of resolvase ( tnpR ) genes carried by a number of mercury resistant soil bacteria has been investigated by DNA sequencing. The resulting DNA sequence information was compared to previously published tnp R. DNA sequences and to previously published restriction fragment length polymorphism (RFLP) data, permitting the relationships between DNA sequencing and RFLP approaches to be studied by the use of phylogenetic trees. DNA maximum likelihood and DNA parsimony were used to construct a variety of phylogenetic trees. DNA sequencing confirmed the validity of RFLP analysis and highlighted the importance of restriction endonuclease choice upon the resulting RFLP patterns and dendrogram topology. The tnp R genes of two previously uncharacterised mercury resistant bacteria, T2–7 and T2–12 were also studied. DNA sequence data placed T2–7 in a previously described gene class, tnp R-D and T2–12 in a new gene class, tnp R-F. The significance of this data with respect to the recombination and evolution events occurring within bacterial populations are discussed.