FIG. 1.

Linkage distance among 231 Medicago-nodulating rhizobia derived from allelic variation among 10 chromosomal loci. A matrix of the strain identification and the ST followed by the allele labels for each was used in the START (Sequence Type Analysis and Recombinational Tests, version 1.05) program to generate the UPGMA dendrogram. The program was written by Keith Jolley, University of Oxford (14). MLST group affiliation is indicated. Singletons are identified by an “s”; ST numbers followed by a blank belong to group 1.