csaB gene analysis clustered 198 strains of Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis into two groups related to mammalian and insect hosts, respectively. Mammal-related group I strains also have more S-layer homology (SLH) protein genes than group II strains. This indicates that csaB-based differentiation reflects selective pressure from animal hosts.
Zheng, J., Peng, D., Song, X., Ruan, L., Mahillon, J., & Sun, M. (2013). Differentiation of Bacillus anthracis, B. cereus, and B. thuringiensis on the basis of the csaB gene reflects host source. Applied and Environmental Microbiology, 79(12), 3860-3863. https://doi.org/10.1128/AEM.00591-13 (Original work published 2013)