ROBERT SIEGEL, HOST:
This is ALL THINGS CONSIDERED from NPR News. I'm Robert Siegel.
MELISSA BLOCK, HOST:
And I'm Melissa Block.
Scientists drew their first rough map of the human genome back in 2000. But parts of our genetic blueprint are still not well understood. Today, researchers unveiled the results of a massive international project that explored parts of our DNA that are not genes, the pieces in between the genes.
As NPR's Rob Stein explains, the effort has produced some surprising findings.
ROB STEIN, BYLINE: For years, scientists thought that most of our DNA was essentially useless, mostly filler between the genes that carry instructions for everything in our bodies. The conventional wisdom was that only a tiny fraction of DNA, the part that has genes, really mattered. There was even a catchy name for this vast genetic wasteland.
MICHAEL SNYDER: The phrase that was thrown around was junk DNA.
STEIN: That's Michael Snyder, a geneticist at Stanford University.
SNYDER: I think all of us would agree that that really wasn't a good term because it was simply something we didn't know what it did.
STEIN: So in 2003, the National Institutes of Health launched the ENCODE Project. More than 400 scientists in 32 labs around the world scoured this supposed junk DNA. They conducted more than 1,600 experiments to try to understand what was really going on there. Today, they unveiled the results in more than 30 papers being published in a slew of leading scientific journals.
Elise Feingold is with the National Human Genome Research Institute.
ELISE FEINGOLD: So the most amazing thing that we found was that we can ascribe some kind of biochemical activity to 80 percent of the genome. And this really kind of debunks the idea that there's a lot of junk DNA.
STEIN: Instead, this DNA is actually teeming with a web of complex molecular switches, switches that play crucial roles in regulating genes. The scientists have found more than four million of these switches so far.
Here's John Stamatoyannopoulis of the University of Washington.
JOHN STAMATOYANNOPOULIS: Most of the human genome is out there to control the genes. In other words, to sort of have the programming of the genome or sort of its operating system, if you will.
STEIN: These DNA switches rev genes up, shut them down. They orchestrate what makes skin cells skin, brain cells brain, and so forth. They choreograph everything for making individuals who they are.
STAMATOYANNOPOULIS: There's a complicated web of connections that run along the genome that sort of specifies how its operations work.
STEIN: Scientists have already started to figure out which switches control which genes. And that's uncovered even more surprises. Genes can get instructions from dozens of these switches. And some of the switches are nowhere near the genes they control.
Stamatoyannopoulis says an early analysis of some of the data appears to explain some of the mysteries about how mutations in DNA make people sick.
STAMATOYANNOPOULIS: The whole way that we look at the genetic basis of disease is going to change. And it's going to change from this model of trying to look at that gene or this gene, et cetera, to trying to look at genes operating as a system or a network.
STEIN: Other scientists hailed the findings as providing crucial new insights. But they warned that the payoff probably won't happen anytime soon.
James Evans is a geneticist at the American College of Medical Genetics.
JAMES EVANS: I think it would be irresponsible and really counterproductive to try to massage this into a situation where you're going to go to the doctor's office in the next year and see these things playing out. That's not the way science works.
STEIN: It'll take years to sort through the millions of combination of genes and genetic switches to sort it all out. But Elise Feingold at the NIH says the ENCODE Project has provided a kind of genetic Google Map to guide the way.
FEINGOLD: It allows researchers to look at the chromosomes and then zoom in to genes, even down to individual nucleotides in the human genome, in much the same way that anyone using Google Maps can do so.
STEIN: That, Feingold says, would help scientists explore what was once dismissed as a meaningless void in our DNA.
Rob Stein, NPR News.