Scientists have come up with a synthetic form of DNA. This new molecule uses structures not found anywhere in nature, to make a truly unique strand of DNA. This synthetic variety is said to be fully functional.
Full story here.
Why is this important? Making a artificial strand on DNA allows you to manipulate its properties on a molecular level. This allows you to tailor make a DNA molecule for a specific purpose. You could use this ability to build a microorganism from the ground up, and design if for a single purpose. For example, you could make a microbe that eats a toxic substance and converts it into harmless waste products. In the long run, this might be far cheaper than conventional disposal methods. These synthetic microbes could also be used to create complex molecules for the pharmaceutical industry. One day they might play a role in energy production.
In the near term, being able to create artificial DNA lets you study how DNA might have developed if its composition was slightly different. This can give us a clue as to the origin of DNA, one of the greatest mysteries in all of science.