Scientists are closer than ever to cracking the hidden code of life itself, having engineered a synthetic bacteria with a "minimum" number of genes needed to support its existence.

The lab-created bacteria -- called Mycoplasma mycoides JCVI-syn3.0 -- contains only 473 genes. That's fewer than any other healthy, replicating cell currently found in nature.

By stripping an artificial cell down to the bare necessities, researchers hope to learn more about how life began on Earth and evolved over time, the study authors said.

"We view life as DNA software-driven and we're showing that by trying to understand that software, we're going to get a better understanding of life," said senior author J. Craig Venter. He's a renowned genetics researcher and founder, chairman and CEO of the J. Craig Venter Institute, a non-profit genomics research group.

However, the most important lesson from this "minimal cell" experiment involves how much scientists don't know about the role that genes play in sustaining life, Venter and his colleagues said.

The study was released online March 24 in the journal Science.

Most of the genes in this synthetic bacteria have a specific job to do. Some play a role in reproduction, others sustain cellular structure and some are needed to maintain the cell's metabolism, the researchers said.

But the scientists couldn't determine a specific biological function for one-third of the genes they needed to keep in the bacteria for it to thrive. These 149 genes needed to be there. But no one knows why.