Craig Venter made news in 2001 when he became one of the first people to sequence the human genome. Nine years later he did it again, helping create the first artificial organism. Now the 68-year-old geneticist is tackling a different challenge: old age. Backed by $70 million from investors such as Draper Fisher Jurvetson and Braintree founder Bryan Johnson, his venture Human Longevity seeks to create the world’s largest genetic database to address conditions such as obesity and cancer. His hope? That medical professionals can use the data to develop treatments so that people can lead longer, healthier lives. Venter is pushing his team in San Diego to map 1 million genomes by 2020. This time, it’s personal. “My own mother just turned 91 this summer,” he admits.