Fig. 1

Evolutionary relationships inside genus Brucella inferred from WG-SNP analysis. a Rooted phylogenetic tree with Brucella sp. 09RB8910 as outgroup. The evolutionary history was inferred by using the Maximum Likelihood method based on the Tamura-Nei model [1]. The tree with the highest log likelihood (−581,757.1726) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach, and then selecting the topology with superior log likelihood value. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The analysis involved 25 nucleotide sequences. There were a total of 114,041 positions in the final dataset. b Unrooted phylogenetic tree showing in more detail the 23 core Brucella genomes, involving a total of 30,255 SNPs in the final dataset and depicting eight clades (A to H). The evolutionary history was inferred by using the Maximum Likelihood method. The tree with the highest log likelihood (−193,253.4180) is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach, and then selecting the topology with superior log likelihood value. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. Evolutionary analyses were conducted in MEGA6