Indian Journal of Microbiology

, Volume 55, Issue 4, pp 384–391 | Cite as

Identification of Recombination and Positively Selected Genes in Brucella

  • Udayakumar S. Vishnu
  • Jagadesan Sankarasubramanian
  • Jayavel Sridhar
  • Paramasamy Gunasekaran
  • Jeyaprakash Rajendhran
Original Article


Brucella is a facultative intracellular bacterium belongs to the class alpha proteobacteria. It causes zoonotic disease brucellosis to wide range of animals. Brucella species are highly conserved in nucleotide level. Here, we employed a comparative genomics approach to examine the role of homologous recombination and positive selection in the evolution of Brucella. For the analysis, we have selected 19 complete genomes from 8 species of Brucella. Among the 1599 core genome predicted, 24 genes were showing signals of recombination but no significant breakpoint was found. The analysis revealed that recombination events are less frequent and the impact of recombination occurred is negligible on the evolution of Brucella. This leads to the view that Brucella is clonally evolved. On other hand, 56 genes (3.5 % of core genome) were showing signals of positive selection. Results suggest that natural selection plays an important role in the evolution of Brucella. Some of the genes that are responsible for the pathogenesis of Brucella were found positively selected, presumably due to their role in avoidance of the host immune system.


Brucella Recombination Positive selection Evolution 



This work was supported by the Department of Biotechnology, New Delhi through DBT-Network Project on Brucellosis. The UGC-CAS, CEGS, NRCBS, DBT-IPLS, DST-PURSE Programs of School of Biological Sciences, Madurai Kamaraj University is gratefully acknowledged.

Compliance with Ethical Standards

Competing Interest

The authors have declared that no competing interest exists.


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Copyright information

© Association of Microbiologists of India 2015

Authors and Affiliations

  • Udayakumar S. Vishnu
    • 1
  • Jagadesan Sankarasubramanian
    • 1
  • Jayavel Sridhar
    • 1
  • Paramasamy Gunasekaran
    • 1
  • Jeyaprakash Rajendhran
    • 1
  1. 1.Department of Genetics, School of Biological SciencesMadurai Kamaraj UniversityMaduraiIndia

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