The discovery that all life is underpinned by a genetic code has changed our understanding of everything in biology. And, yet, given that DNA is thousands of times smaller than a human hair, most of the applications that involve its use have remained restricted to sophisticated labs. No longer. Over the past decade, miniaturization of computers and lab equipment has made high-tech tools portable. The latest such advancement is the stuff of science fiction: a group of scientists in the US and Sweden have developed a DNA-analyzing kit that can run on a smartphone. To understand how it works, consider the example of tuberculosis. When a patient in, say, rural India is diagnosed with the disease, a doctor without access to a sophisticated lab will typically give the patient drugs from the first line of treatment. However, one in four patients won't respond to this treatment, because the bug they've caught is resistant to these drugs. Without a test to determine which strain the patient is