Your genome contains all of your genetic information, and it's pretty long - the Human Genome Project estimated that humans have between 20,000 and 25,000 genes. But according to synthetic biology, you can survive on only 473! At least a very simple bacterium can. Of this "minimal genome", scientists previously didn't know what nearly a third actually did. But now Mark Wass has been telling Heather Jameson how his team at the University of Kent may have cracked 66 of the mystery genes...