The Last Word On Nothing

Last week, officials said that DNA from multiple family members was used to confirm that its years-long hunt for Osama bin Laden had ended in success.

But even as politicians criticized President Obama’s decision not to release photos of the dead bin Laden, nobody questioned the assertion that, thanks to DNA, US officials are “99.9” percent certain that the man they shot and killed in a compound in Abbottabad, Pakistan, was the long-sought al Qaeda leader.

Instead, Republicans and Democrats alike hailed the DNA evidence as “conclusive,” proving “beyond the shadow of a doubt” that the dead man was bin Laden, and the public took them at their word.

I’m not questioning the fact that DNA testing, if done properly, would be a powerful confirmation of bin Laden’s identity, or that the US got the right man in Pakistan. Even al Qaeda has conceded that bin Laden is dead.

But the lack of public demand for details of the DNA testing is a fascinating statement about our collective faith in this molecule.

It’s the latest manifestation of our DNA romance – our belief in the transcendent power of the double helix.

That belief has spread through pop culture via television shows like “CSI: Crime Scene Investigation,” which portray DNA matching as a yes-or-no, black-and-white process. Bioethicist Jonathan Moreno, of the University of Pennsylvania, also credits initiatives like the Innocence Project, which has used DNA to exonerate hundreds of falsely accused prisoners. That has further strengthened our belief in the righteous truth-telling power of DNA.

We understand that photographs can be faked. But DNA seems somehow special and infallible.

Unfortunately, the US government doesn’t have a stellar record in major terrorism investigations that hinge on DNA evidence.

This February, a panel of independent scientists convened by the US National Academies criticized the DNA analysis methods used in the Federal Bureau of Investigation’s Amerithrax case – the hunt for the killer who mailed anthrax around the country in 2001. The panel said the FBI used outdated science in the analysis that supposedly pegged former Army microbiologist Bruce Ivins as the sole perpetrator of the attacks.

The bin Laden identification was apparently not conducted by the FBI. On May 7, a senior intelligence official told reporters that the Central Intelligence Agency and the Department of Defense conducted independent DNA analyses of a “comprehensive DNA profile derived from bin Laden’s large extended family.”

“Based on that analysis, the DNA is unquestionably his,” the official said, estimating the probability of a mistaken match at one in 11.8 quadrillion.

But he didn’t say how many relatives yielded the DNA, who they were, or what type of DNA was tested.

All of these factors make a big difference in how confident we can be that the US got the right guy.

There are plenty of good reasons why the US shouldn’t release details of its DNA testing, of course, says Stanford University bioethicist Hank Greely. Disclosing which bin Laden relatives donated their DNA might endanger them. And revealing that some relatives may have unwittingly donated DNA opens up a whole different can of worms. The government probably also doesn’t want to reveal much about how it collects and analyzes DNA evidence.

Which seems to be just fine with the American public.

In fact, our willingness to accept the mention of DNA evidence at face value is a very interesting argument against the oft-heard lament that a lack of scientific literacy is undermining the public’s support for science.

True, many of us may not be able to define what DNA is. But perhaps it’s that very ignorance that engenders our high regard for all things genetic.

After all, we can’t question what we don’t understand.

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Photo credit Alfred Stevens, Truth and Falsehood, Victoria and Albert Museum, London. Photo by Marko Vallius, mvallius/flickr.