Scientists from around the world reported Wednesday that they've made major progress in identifying where genes exist and what they do, while also discovering that most "junk" DNA isn't junk after all.
The breakthroughs -- made by a team of scientists in the ENCODE project -- represent a major step toward the ultimate goal of being able to quickly identify and treat a wide variety of genetic diseases. (Overview).
The advances come roughly 10 years after the sequencing of the human genome, an event that seemed to bear little fruit at first. But scientists discovered that a lot of the "junk" DNA that was thought to have little or no function plays a major role in the behavior of genes.
"It used to be thought that most of the coding was done by 2 or 3 percent of the genome," said Joe Ecker, a plant biologist at the Salk Institute who wrote an overview of ENCODE. "But new studies show that about 80 percent of the genome has some biological function. Some of those functions are hidden in the 'junk.' ''
Ecker added that ENCODE scientists have "interpreted the first words of the language in the genome. We don't understand the whole dictionary. But in five years, we'll be saying that we didn't know anything at this point."
Eric Topol, the cardiologist who runs the Scripps Translational Science Institute in La Jolla, and is chief academic officer of Scripps Health, said, "This 'smorgasbord' of new data on the genome resets our understanding of how most of the action—and that which influences diseases and health—is not occurring in genes per se, but rather in the rest of the genome which was originally labeled “junk DNA.
"Many critical pathways and networks of the genome have now been identified through this work that play a key role across multiple diseases.
"Basically we move away from the gene-centric (the 1.5% coding elements) thinking to genome-centric (the other 98.5%). What is fascinating is that hundreds of thousands of letters away a base (nucleotide, letter) can influence another base somewhere remote in the genome."
Much of this work was done with sequencing equipment that came from Illumina and Life Technologies, a pair of San Diego companies.