A gene circuit works a bit like an electronic one, only all its components are biological. Gene circuits include dozens of genes, plus the proteins needed to read those genes. Together, the genes and proteins perform a task. There are natural gene circuits, such as the genes and proteins that work together to perform photosynthesis in plants. On these paper tickets, however, scientists are able to design any circuits they like, not just naturally-occurring ones. They might mix together genes from different species, for example, to get the paper to react how they want. The team that developed the paper slips, including biologists and engineers from Boston and Chevy Chase, Maryland, came up with a circuit that triggers color changes after detecting specific genetic material—such as genes from certain bacteria, or those Ebola viruses.