Table 4. Comparison of the taxonomic distribution of virulence genes and randomly selected genes of B. melitensis 16 M within Proteobacteria group.
| Bacteria group | Taxonomical classification | Random genes (N = 250) | Virulence genes (N = 160) | Comparison |
| Proteobacteria | Phylum (N) | N, % (A.P.) | N, % (A.P.) | P value |
| Alphaproteobacteria (92) | 9691, 35.03 (26.08) | 7407, 35.62 (26.24) | 0.18 | |
| Betaproteobacteria (54) | 5057, 18.28 (18.16) | 3851, 18.52 (18.66) | 0.50 | |
| Deltaproteobacteria (29) | 2148, 7.77 (14.87) | 1704, 8.19 (15.84) | 0.08 | |
| Epsilonproteobacteria (21) | 1086, 3.93 (19.57) | 846, 4.07 (20.31) | 0.43 | |
| Gammaproteobacteria (120) | 9679, 34.99 (21.32) | 6986, 33.60 (18.95) | 0.001* | |
| Total (316) | 27661, 100 (100) | 20794, 100 (100) | ||
| Alphaproteobacteria | Caulobacterales (5) | 589, 6.08 (9.54) | 464, 6.26 (10.14) | 0.62 |
| Magnetococcales (1) | 76, 0.78 (6.86) | 59, 0.80 (7.15) | 0.93 | |
| Parvularculares (1) | 103, 1.06 (12.51) | 76, 1.03 (12.42) | 0.81 | |
| Rhizobiales (37) | 4841, 49.95 (10.44) | 3732, 50.38 (10.92) | 0.58 | |
| Rhodobacterales (11) | 1375, 14.19 (10.33) | 1062, 14.34 (10.77) | 0.78 | |
| Rhodospirillales (9) | 1000, 10.32 (10.97) | 792, 10.69 (11.81) | 0.43 | |
| Rickettsiales (20) | 941, 9.71 (14.68) | 634, 8.56 (13.36) | <0.01* | |
| Sphingomonadales (6) | 597, 6.16 (9.98) | 477, 6.44 (10.73) | 0.46 | |
| Unclassified (2) | 169, 1.75 (14.69) | 111, 1.50 (12.70) | 0.21 | |
| Total (92) | 9691, 100 (100) | 7407, 100 (100) |
N = Number, A.P.: adjusted percentage, this is the corresponding percentage of the number of orthologs per each 100 genes of each organisms and divided by the number of organisms in each group, P value obtained with chi-squared test and Fisher exact test,
*p value ≤0.05. In order to understand the differences in the percentages between the groups, the percentage and not the adjusted percentage must be taken into account, the adjusted percentage should only be considered in descriptive results, i.e., to know the distribution of orthologs in the organisms groups in each set of genes.