Article Dans Une Revue Molecular Microbiology Année : 2002

Differences in chromosome number and genome rearrangements in the genus Brucella

Estelle Jumas-Bilak
Sylvie Michaux-Charachon
  • Fonction : Auteur
Gisèle Bourg
  • Fonction : Auteur
David O'Callaghan
  • Fonction : Auteur
Michel Ramuz
  • Fonction : Auteur

Résumé

We have studied the genomic structure and constructed the Spe I, Pac I and I‐ Ceu I restriction maps of the four biovars of the pathogenic bacterium Brucella suis . B . suis biovar 1 has two chromosomes of 2.1 Mb and 1.15 Mb, similar to those of the other Brucella species: B . melitensis , B . abortus , B . ovis and B . neotomae . Two chromosomes were also observed in the genome of B . suis biovars 2 and 4, but with sizes of 1.85 Mb and 1.35 Mb, whereas only one chromosome with a size of 3.1 Mb was found in B . suis biovar 3. We show that the differences in chromosome size and number can be explained by rearrangements at chromosomal regions containing the three rrn genes. The location and orientation of these genes confirmed that these rearrangements are due to homologous recombination at the rrn loci. This observation allows us to propose a scheme for the evolution of the genus Brucella in which the two chromosome‐containing strains can emerge from an hypothetical ancestor with a single chromosome, which is probably similar to that of B . suis biovar 3. As the genus Brucella is certainly monospecific, this is the first time that differences in chromosome number have been observed in strains of the same bacterial species.

Dates et versions

hal-04738876 , version 1 (15-10-2024)

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Citer

Estelle Jumas-Bilak, Sylvie Michaux-Charachon, Gisèle Bourg, David O'Callaghan, Michel Ramuz. Differences in chromosome number and genome rearrangements in the genus Brucella. Molecular Microbiology, 2002, 27 (1), pp.99-106. ⟨10.1046/j.1365-2958.1998.00661.x⟩. ⟨hal-04738876⟩
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