Humans have somewhere around 20,000 genes, and scientists don't know what most of them do. Even simpler bacterium commonly used in scientific experiments have 4,000 to 5,000 genes. If scientists could figure out the minimum number of genes necessary for life, they reasoned, that is the perfect starting point to determine the functions of those genes.

Now a team led by scientists from the J. Craig Venter Institute in California has synthesized a cell with what they've determined is the smallest number of genes necessary for life: 473. Their research, published today in Science, answers a fundamental question in biology, and may soon make a la carte synthetic cells available for medical and industrial applications.