BIOTERRORISM: How scientists identified anthrax used in bioterrorism

Washington, March 9 (IANS) It took nearly a decade before researchers were allowed to talk about their work identifying the anthrax strain used in the 2001 deadly letter attacks.
University of Maryland researchers have since developed their work into a genetic 'fingerprinting' tool that is available online to law enforcement seeking to track down other microbial suspects.
'We found unique bio-markers to help investigators track down the source of the anthrax,' said Steven Salzberg, director of the Maryland Centre for Bioinformatics and Computational Biology (CBCB), the journal Proceedings of National Academy of Sciences reports.
'At first, the tiny mutations were elusive. We thought we'd pieced together the 'jigsaw puzzle' of data very neatly, until we ended up with a few oddball bits left over. When we looked more closely, we found an extra copy of a critical gene,' said Salzberg.
Mihai Pop, Salzberg's colleague and study co-author, said: 'Fortunately, anthrax bacteria mutate relatively slowly, so the material in this colony developed these small distinctive mutations that resulted in physically distinct characteristics.'
'If you isolate a colony of bacteria in a test tube, they'll slowly accumulate random mutations that make them distinct from any other samples of the same type of bacteria,' said Pop, according to a Maryland statement.
Salzberg said: 'Our colleagues at the University of Maryland... sequenced the DNA of the bacterial samples provided by the FBI (Federal Bureau of Investigation). Then, using computational analysis, we identified four tiny changes in the DNA structure that the FBI could use as a fingerprint in their investigation.

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