“A person commits a crime, and the detective uses DNA evidence collected from the crime scene to track the criminal down. An outbreak of foodborne illness makes people sick, and the U.S. Food and Drug Administration (FDA) uses DNA evidence to track down the bacteria that caused it. Sound far-fetched? It’s not. The FDA has increasingly used a complex, cutting-edge technology called whole genome sequencing to support investigations of foodborne illnesses. Put as simply as possible, whole genome sequencing is a rapid way of figuring out the order of DNA nucleotides, or bases, in a genome—the order of As, Cs, Gs, and Ts that make up the DNA of all living things. The human genome is made up of nearly 4 billion of these genetic letters in sequence. Bacteria have many fewer genes and genetic letters. When it comes to outbreaks, scientists study the genome of the bacteria that cause disease, called pathogens.”