By Erika Check Hayden | May 26, 2011 | 5 Comments
I will never forget the last time I got serious food poisoning. I was a teenager, and my family went out to eat one sunny Saturday morning. Soon after we returned home, I was grasping the toilet bowl, retching in agony. I could still taste the omelet I had eaten for breakfast.
To this day, I’m not a big fan of eggs.
I was reminded of this last week when researchers published a paper claiming to find evidence that the genetic code is not so faithfully interpreted by our cells as we’ve come to believe. The claim, if true, is astonishing: it would mean that the long-accepted central dogma of molecular biology is, at best, incomplete.
The central dogma describes how cells interpret the instructions encoded in our DNA, which is made up of four bases strung along in particular sequences. The central dogma says that the sequence of these bases is preserved when the DNA is read into a messenger molecule, called RNA, and that this sequence determines the identity of the protein ultimately made from that RNA template. But the new research, published on 19 May in Science, claims that there are thousands of instances where DNA and its corresponding RNA differ in sequence. These “mismatches,” created by a process called RNA editing, happen far more often than anyone had guessed, the paper reported.
Most genome scientists called the finding exciting – if it holds up. But soon, statisticians began arguing that computational errors could have created the false appearance of DNA-RNA mismatches. The authors of the paper stood by their work.
The whole situation – a high-profile paper in a top-tier journal encountering immediate, damning criticism – felt a bit familiar to some biologists. One researcher in the Netherlands joked via Twitter last week: “perhaps the RNA editing is caused by inclusion of arsenic in DNA backbone?”
He was referring to a different Science paper, published in December, that also made an explosive claim: that bacteria can grow using arsenic rather than phosphorous to build their DNA, even though the former is toxic to life on earth. Soon after it was published, researchers pounced upon the paper in the blogosphere, pointing out what they called technical shortcomings of the work. It’s hard to find anyone in the arsenic microbiology field who believes the paper’s conclusions today, but the authors still defend their work, and are slated to respond to many of the criticisms in an upcoming issue of Science.
There are crucial differences between the arsenic story and the RNA mismatch story. The arsenic paper, for instance, was hyped in advance by a NASA press release that made titillating claims about an “astrobiology finding that will impact the search for evidence of extraterrestrial life,” then boasted that the finding would “alter biology textbooks.”
The authors of the RNA paper have been more reserved, refusing to say, for instance, that their work imperils the central dogma. And their critics have respectfully admitted that their concerns might be proven wrong, and that the work suggests “an interesting and potentially important phenomenon in humans.”
What’s unfortunate is the way that one mishandled “breakthrough” can taint others that come after, whether they turn out to be legitimate or not. So the next time we hear that biology has been upended by a striking new finding, we can’t help but think of the last time that happened…and of the scientific indigestion that we suffered as a result.
When hype dissolves into hot air, it leaves a bad taste in our mouths – and ends up splattering egg all over the faces of responsible researchers, too.
Photo credit: nebarnix/flickr.