Position of IS 711 copies in the chromosomes of the published Brucella genomes. The two blocks contain the large and the small chromosomes respectively. Key to the species: S, B. suis; M, B. melitensis; A9, B abortus 9_941; A8, B abortus 2308; O, B. ovis. Common copies numbered from 1 to 6 are marked on the top. xs, xiii, x-08 and xa are IS711 species specific copies. The inverted segment of B. abortus chromosome II is marked in grey.