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United States Department of Agriculture

Agricultural Research Service

Title: Repetitive Dna, Chromosomal Rearrangements, and Phenotypic Variation in Leptospira

Author
item Zuerner, Richard

Submitted to: American Society for Microbiology Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 7, 1995
Publication Date: N/A

Technical Abstract: Pathogenic members of the genus Leptospira cause leptospirosis, a widespread zoonotic disease. Leptospira spp. are spirochetes and belong to one of the most ancient branches of eubacteria. Analysis of the leptospiral genome reveals several interesting and unusual features. The 4.75 Mb genome is segmented into two distinct circular chromosomes (4.4 Mb and 350 Kb). Comparison of genetic organization of different strains shows that the genome is fluid, possessing several large rearrangements. There are also several different species of repetitive DNA present in the genome including insertion sequences. Often chromosomal rearrangements are closely linked to repetitive DNA species, suggesting that the rearrangements occur via recombination between like copies of repetitive DNA. Hybridization analysis of isolates from different geographical regions using IS element probes allows the isolates to be categorized into discrete genetic groups. These genetic groups are found associated with specific geographical regions. Differences in the epidemiology of leptospirosis coincide with different genetic groups. We hypothesize that chromosomal rearrangements results in virulence-associated phenotypic changes in the bacteria. By studying leptospiral repetitive DNA species and their role in generating rearrangements we should better understand how these rearrangements affect changes in gene expression affecting virulence.

Last Modified: 4/19/2014
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