Biological warfare attracts some troubled scientists

Perhaps Bruce Ivins was responsible for the anthrax attacks.

On the one hand, the Bush FBI's credibility is negative. That is, if the FBI told me the sun was shining I'd get an umbrella. In that vein it's noteworthy that they keep tweaking their leaks...

Doubts over the anthrax case intensify -- except among much of the media - Glenn Greenwald - Salon.com

... What did the FBI do in response to that rather devastating hole in its theory being pointed out? It just leaked a completely different story to the Post about when and how Ivins mailed ...

On the other hand there are supposed technical developments ...

The Anthrax Case: From Spores to a Suspect -- Enserink 2008 (812): 1 -- ScienceNOW
By Martin Enserink

The scientific evidence against Bruce Ivins, the 62-year-old Army scientist who killed himself while about to be indicted for the anthrax murders, is finally emerging. Last week, the Federal Bureau of Investigation (FBI) laid some of its cards on the table. One key document, scientists say, now enables a reconstruction of the trail that led the FBI from the deadly letters back to Ivins's lab at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) in Fort Detrick, Maryland...

... The key to understanding the investigation is that the anthrax used in the attacks didn't have a single, uniform genetic makeup, a source close to the investigation says. Each of the envelopes likely contained many billions of spores; within such a population, there are always subpopulations of cells bearing mutations that set them apart from the majority. The same minorities would presumably have been present in the "mother stock” of anthrax from which the spores were prepared.

However, standard sequencing--which would require the DNA from thousands of spores--would have resulted in a "consensus sequence" for the spores, in which such rare mutations were simply drowned out. To find them, researchers used a different technique: They grew spores from the envelopes on petri dishes, generating hundreds or even thousands of colonies per dish, each the progeny of a single spore. They then searched for colonies that looked different from the majority; the affidavit mentions variations in "shape, color, texture."... Next, they set out to find the mutations that made those colonies different.

To do that, the FBI used a brute-force approach: It had the entire genomes of the bacteria in the minority sequenced. TIGR--which merged into the J. Craig Venter Institute in 2006--sequenced "probably somewhere between 10 and 20" such genomes in the years after the attacks, Salzberg says. TIGR could not handle live anthrax cells itself; the FBI gave the lab purified DNA ...

Comparing the sequence of the variant colonies to an original B. anthracis strain called Ames, widely used in research, identified a number of mutations, says Salzberg; they included single-nucleotide polymorphisms, a change of a single base pair, and tandem repeats, in which a short piece of DNA is repeated a variable number of times.

The FBI then had scientists at other labs develop tests that allowed them to screen any anthrax sample for four of these mutations....

... with the four tests, the FBI examined more than 1000 anthrax isolates, collected from 16 labs that had the Ames strain in the United States and several more in Canada, Sweden, and the United Kingdom. In only eight of those samples, they found all four mutations seen in the envelope samples; and each of these eight, the affidavit says, was "directly related" to a "large flask" of spores, identified as RMR-1029, which Ivins had created in 1997 and of which he was the "sole custodian."

... It's also unclear how many of the 1000 samples had fewer than four, but more than zero, of the mutations. "If a whole bunch of them had two or three," that would increase the odds that the perfect match at USAMRIID was just a false positive...

... Science aside, the affidavit relies heavily on circumstantial evidence...

One of the weak points in the affidavit is Ivins's motive, says Gregory Koblentz, a biodefense specialist at George Mason University in Fairfax, Virginia... A glaring omission, meanwhile, is any evidence placing Ivins in Princeton, New Jersey, on any of the days the envelopes could have been mailed from there...

I'll take the skeptical side of things. The FBI has shown a nasty combination of incompetence and aggressiveness over the past decade. There's no evidence that they've reformed.

On the other hand, there's some reason to suspect that biological warfare attracts troubled scientists. The innocent Steven Hatfill was a convenient FBI fall-guy because of a murky past and questionable judgment. Bruce Ivins probably suffered from lifelong mental illness, perhaps a variant of paranoid schizophrenia.

Maybe we ought to be doing a better job of evaluating people who want to work with bioweapons?

Just saying.