If you know a bit of biology, you might know that the genetic code of DNA is written in just four ‘letters’ - A, C, T and G. You may even know that these letters are the initials come from the names of the molecules that make up the double helix, known as nucleotide bases: adenine, cytosine, thymine and guanine. But where did those strange-sounding names come from? In this episode of Genetics Unzipped, we go from poop to pus to atomic bonds on our journey to learn about the discovery of these vital chemicals and how they got their names.