Researchers have discovered that parts of our DNA formerly believed to be inactive play an extremely important role.

From the New York Times:

The human genome is packed with at least four million gene switches that reside in bits of DNA that once were dismissed as “junk” but that turn out to play critical roles in controlling how cells, organs and other tissues behave. The discovery, considered a major medical and scientific breakthrough, has enormous implications for human health because many complex diseases appear to be caused by tiny changes in hundreds of gene switches.

Among the diseases that may depend on the action of these genetic switches are cancer, multiple sclerosis and lupus. Other conditions, such as diabetes, depression and high blood pressure, may also be affected by these switches.

In fact, it sounds as if understanding these genetic mechanisms might take us very close to understanding why one person is different from another in all kinds of ways.  

And, on a political note, it should be noted that the federal government played a crucial role in this research:

The findings are the fruit of an immense federal project involving 440 scientists from 32 labs around the world.

http://www.nytimes.com/2012/09/06/science/far-from-junk-dna-dark-matter-proves-crucial-to-health.html?pagewanted=1&_r=1&hp