Viagra and CRISPR

Viagra’s effects on men were first discovered as an unexpected side-effect during trials for a medication meant to help patients with a heart condition. CRISPR cas– 9 is now a tool that can be used to modify and replace genes – but it was first noted as a random collection of genes. In the first of three episodes about the genius of accidents in science, Professor Adam Hart explores how, sometimes, the results you’re looking for are not as important as those that appear unexpectedly. Picture: Test Tubes, Credit: Grafner/Getty Images Producer: Rory Galloway