Ages: Venter, 64; Gibson, 34
Occupations: Molecular biologists and genetic engineers
Previous TIME 100 appearances: Venter, 2; Gibson, 0
Venter and Gibson are co-leaders of the team that created the first synthetic cell at the J. Craig Venter Institute's lab in Rockville, Md. Building on earlier work, they created a synthetic copy of a bacterial chromosome and inserted it into a different species of bacterium, where it not only replaced the organism's DNA but also went to work. The process is still laborious and prohibitively expensive, but it's a solid step toward truly artificial life.