Author
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Halling, Shirley |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 9/15/2003 Publication Date: 9/15/2003 Citation: Halling, S.M. 2003. Comparison of the genomic sequences of brucella melitensis, brucella suis, and brucella abortus boivars: structure and pseudogenes [abstract]. Brucellosis 2003 International Research Conference. p. 44. Interpretive Summary: Technical Abstract: The whole genomic sequences of three classical species of Brucellae, Brucella melitensis, Brucella suis and Brucella abortus have been determined and the sequence of Brucella ovis is nearly finished. These species preferentially infect goats, swine, bovine, and sheep, respectively. Comparative genomics may aid in answering questions related to species specificity, virulence, pathogenicity, as well as phenotypic differences observed among the Brucellae. The close taxonomic relationship of Brucellae to the plant symbiont Sinorhizobium meloti is supported by the extensive gene synteny between their genomic sequences, especially the large chromosome of Brucellae. The genomic sequences excluding insertion/deletions (indels) are more than 99% similar to each other; there are only 7,301 SNPs between B. suis and B. melitensis among 3.2 Mbp. These are more or less randomly, but not evenly spread, through out the chromosome. The determination of the genomic sequences of several Brucellae confirmed the pulsed field maps revealing that most Brucellae have two circular chromosomes. The pulsed field maps also revealed an inversion within the small chromosome of B. abortus 544 biovar 1. The inversion was also found within B. abortus biovars 2 and 4 but not biovars 3, 5, 6, and 9. There are several large indels encoding phage associated proteins that are found among the genomic sequences, but none of these are unique to a single species. All three sequences have the large putative transposable element, Tn1953, that encodes a large number of sugar and amino acid transport proteins. Pseudogenes were identified among the Brucellae. These were due mostly to premature stops caused by SNPs or to repeated sequences being involved in either deletions or differences in copy numbers. The same pseudogene was rarely shared by all three Brucellae. |
