Researchers have sequenced the 5.2-million base pairs in the genome
of the Ames strain of Bacillus anthracis, confirming
that the powder used in the 2001 mail attacks is virtually identical to the
most widely used research strain. Just 11 base pairs differ between the two.
With funding from the National Institute of Allergy and Infectious Diseases,
scientists at the Institute for Genomic Research, Rockville, Md, also found
that circular DNA molecules called plasmids account for most of the pathogen's
virulence. A comparison to related Bacillus species
turned up evidence that plasmids can shuffle between species, possibly increasing
the overall virulence of each strain (Nature. 2003;423:81-86).
Vastag B. Anthrax Decoded. JAMA. 2003;289(19):2491. doi:10.1001/jama.289.19.2491-a