Almost a decade ago, a team of international researchers completed the first rough map of 25,000 individual genes that make up the human genome - which is essentially a blueprint for producing a human being.
The achievement was hailed as a major scientific breakthrough that would revolutionize medicine. But despite all the hoopla, the researchers really didn't have much of a grasp on how the genome actually works.
This week, however, their understanding finally took a big leap forward with the completion of the first map of the so-called epigenome - an extra layer of genetic coding that regulates individual genes.
"This is a tool that will allow us to see things we have never seen before," said Joseph Ecker a professor at the Salk Institute in La Jolla, Calif., and senior author of the report published by the journal Nature.
He noted that each cell in an individual's body contains the same basic genetic information. What makes one cell different from another is that fact that different genes are active.
Dr. Ecker said the epigenome is the key to understanding what turns genes on and off, "like stop and go signposts" superimposed on top of the overall genome.
What's more, scientists believe the epigenome can be altered by environmental factors, ranging from diet to pollution, and disrupt this finely tuned regulatory process, setting the stage for various illnesses including cancer and heart disease.
By learning how the epigenome works in different cell types, researchers hope to gain new ways to treat and prevent numerous diseases. For this first study of its kind, the team of American and Australian researchers produced an epigenome map of a stem cell and a lung cell. Similar mapping efforts are now under way on other cells.