David Ropeik is an international consultant in risk perception and risk communication, and an Instructor in the Environmental Management Program at the Harvard University Extension School. He is the author of How Risky Is It, Really? Why Our Fears Don’t Always Match the Facts and principal co-author of RISK A Practical Guide for Deciding What’s Really Safe and What’s Really Dangerous in the World Around You. He writes the blog Risk; Reason and Reality at Big Think.com and also writes for Huffington Post, Psychology Today, and Scientific American.
He founded the program “Improving Media Coverage of Risk,” was an award-winning journalist in Boston for 22 years and a Knight Science Journalism Fellow at MIT.
The post below was written in the days immediately after the release of the ENCODE papers and includes both a foolish factual error and a tone which, upon reflection and with feedback from many critics, is harsh. A subsequent post at Risk: Reason and Reality “New Evidence About DNA, and Old Patterns of Resistance to New Ideas” attempts to rectify the error and make my argument more respectfully.
In what should be another blow to the hubris of human intellect, we have a new entry in the long and ever growing list of “Really Big Things Scientists Believed” that turned out be wrong. This one is about DNA, that magical strand of just four amino acids*, Adenine paired with Thymine, Cytosine paired with Guanine, millions of those A-T and C-G pairs linked together in various combinations to make the genes that spit out the blueprints for the proteins that make us. Or so science believed.
The problem was that, the ‘genes’ sections of DNA that coded for proteins only came to about 1.5% of the whole 2 meter-long strand. For decades molecular biologists didn’t know what the rest of the DNA…as in, nearly all of it…does. So, in a remarkable stroke of intellectual arrogance, they dismissed it as ‘junk’. Actually, the drier academics simply called it ‘non-coding DNA’. A Japanese scientist named Susumu Ohno called it junk, and the word stuck because, basically, scientists had no explanation for what most of DNA was for. So they assumed it was left over from evolution, had no current function, and was, literally, junk. As Francis Crick, one of the Nobel Prize winners for helping discover the structure of DNA, put it, non-coding DNA has “little specificity and conveys little or no selective advantage to the organism”. Right. As though nature would waste that much energy.
Well, there’s going to be a lot of editing on Wikipedia in the days and weeks to come, and it’s time to reprint the basic biology textbooks, because extensive research into the mystery of what most of DNA is doing there has discovered that the ‘junk’ isn’t junk at all. Most of it has all sorts of jobs. Science Journalist Ed Yong has written a wonderful summary of this work here. The nut of it is:
“A massive international project called ENCODE – the Encyclopedia Of DNA Elements – has moved us from “Here’s the genome” towards “Here’s what the genome does”. Over the last 10 years, an international team of 442 scientists have assailed 147 different types of cells with 24 types of experiments. Their goal: catalogue every letter (nucleotide) within the genome that does something.
“For years, we’ve known that only 1.5 percent of the genome actually contains instructions for making proteins, the molecular workhorses of our cells. But ENCODE has shown that the rest of the genome – the non-coding majority – is still rife with “functional elements”. That is, it’s doing something.”
In many ways, this puts us back to the ABCs of DNA. So toss out a lot of what you know. Only, that won’t be easy. Given the nature of human cognition, it is innately difficult to let go of what you ‘know’ and keep a truly open mind. Just look at history. Big ideas, once set into place and ascribed to by the ‘experts’ in a given field, are hard to get people to think about in new ways. This intellectual inertia can do great harm.
Since the ancient Indians and Chinese and Greeks the belief was that ‘miasma’, bad or vile air, spread disease. In 1847 Ignaz Semmelweis realized that dirty hands were spreading disease at a Vienna obstetrical hospital and had nurses wash their hands, reducing the death toll (earning him the name “The Savior of Mothers). “It’s Miasma”, maintained mainstream doctors, whose intellectual inertia condemned countless millions to illness and death that could have been avoided with simple sanitary procedures that did not become widespread for decades. (Semmelweis died an embittered drunkard.)
Five years later John Snow pioneered epidemiology when he investigated a cholera outbreak in London and figured out that the people getting sick were drinking from one well…that the germ was apparently water-borne. He took it upon himself to remove (steal) the pump handle, and shut off the outbreak. Yet leading English health officials debunked Snow’s finding and clung to the idea of ‘miasma’. After all, they said, note how bad the Thames smells. It was that ‘Great Stink’ more than Snow’s discovery that water carries germs that finally got London to clean up its drinking water.
In the 1890s Dr. William Halstead, a surgical pioneer of great influence at the time, established radical mastectomy as the gold standard of treatment for breast cancer, and despite early evidence that it did little good compared to less traumatic approaches (basically, none of them worked), oncologists refused to abandon Halstead’s approach as late as the 1970’s (see The Breast Cancer Wars), condemning tens of thousands of women to unnecessary suffering and disfigurement.
Despite strong evidence questioning the efficacy of the Prostate Specific Antigen (PSA) test, many urologists still cling to it as the established way to detect prostate cancer, and cling to radical treatments rather than “watchful waiting” even for tumors diagnosed as slow growing, condemning tens of thousands of men to sexual impotence and urinary incontinence who need not suffer those harms
Consider how this intellectual version of Newton’s First Law…an object at rest tends to stay at rest (a big idea once accepted by experts tends to stay accepted)…bears on some huge current health issues. A few scientists (Carlos Sonnenschein and Ana Soto among them) are daring to question the fundamental idea of how cancer starts….the somatic mutation theory that cancer is caused from mutations to the genes that control cell growth. They have found tumors with no evidence of DNA mutation, and offer a different idea about carcinogenesis. Many in the mainstream science community are treating them like Semmelweis and Snow.
A fresh way of doing toxicology – the study of poisons – has found strong evidence to suggest that things that are bad for us at high doses may actually either do no harm or even be good for us at low doses. (In one study that compared rats exposed to low doses of DDT to rats not exposed at all, the rats exposed to low doses of DDT had less liver cancer. Sukata, et.al, 2002 )
You will not be surprised to learn that Ed Calabrese, the main proponent of this theory, known as hormesis, is getting the Semmelweis/Snow treatment.
Because our brain is constantly called on to make choices and judgments – and rarely has all the facts or all the time necessary to go get the facts or all the smarts necessary to understand all the facts, what Herbert Simon called “Bounded Rationality” – human cognition has developed a wonderful range of mental shortcuts for making these judgments. One of them is to default to the way things are ‘framed’. The way we learn things, especially if we learn them from ‘the experts’ or other trusted sources, establishes The Way It Is, and we tend to fight back against, to resist, information that conflicts with that initial framing. (Pluto will always be a planet to me.) It would take time, attention, effort – literally calories spent by the brain – to keep a completely open mind and think everything through afresh every time some new evidence comes in.
This resistance to new ideas is particularly acute, of course, among people who have a vested interest in The Way It Is, professionals whose careers and funding, and self-identity, depend on The Accepted Paradigm. This is uniquely true of academics, and scientists.
But this innate facet of human cognition, that narrows our thinking and causes us to resist new ideas, puts us at risk. Science is not knowledge. Science is the process of methodically testing ideas to see where the bulk of the evidence lies, and requires the effort of an honestly open mind. The ENCODE DNA evidence has great promise. But beyond all the physical things it can teach us, it should serve as another warning that, in the name of human health, and progress, we need a little more humility about what we claim we ‘know’ (come on, could all that DNA really have just been JUNK?), and a lot more humility about the innate limits on our capacity to think and reason and establish ‘the truth’ in a purely objective way.