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DNA relatedness among Bacillus thuringiensis serovars
1National Center for Agricultural Utilization Research, U.S. Department of Agriculture, Peoria, Illinois 61604.
International Journal of Systematic Bacteriology
|January 1, 1994
Summary
Genetic analysis of Bacillus thuringiensis serovars reveals distinct but closely related groups. DNA reassociation shows high intragroup relatedness, with some serovars forming multiple distinct genetic clusters.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Bacillus cereus and Bacillus thuringiensis are closely related bacterial species.
- Understanding their genetic relationships is crucial for taxonomy and strain differentiation.
Purpose of the Study:
- To assess the genetic relationships among common Bacillus thuringiensis serovars and Bacillus cereus using DNA reassociation.
- To determine the degree of genetic relatedness within and between different serovars.
Main Methods:
- DNA reassociation experiments were conducted on multiple strains from 13 common Bacillus thuringiensis serovars.
- Levels of intragroup and intergroup DNA relatedness were quantified.
- Phenetic analysis was used to group serovars based on DNA relatedness.
Main Results:
- Most Bacillus thuringiensis serovars exhibited high intragroup DNA relatedness (90-100%).
- Serovars canadensis and kenyae showed distinct genetic subgroups with lower intergroup relatedness.
- Eleven phena were identified, with three phena containing multiple serovars, indicating genetic overlap.
- Genetic relatedness between Bacillus cereus and Bacillus thuringiensis strains ranged from 65-70%.
Conclusions:
- Many Bacillus thuringiensis serovars are genetically distinct yet closely related.
- DNA reassociation is a valuable tool for resolving genetic relationships within the Bacillus cereus group.
- The findings support the close genetic ties between Bacillus cereus and Bacillus thuringiensis.