According to Dr. John Stamatoyannopoulos, University of Washington, associate professor of genome sciences and of medicine, for over forty years it has been assumed that DNA changes affecting the genetic code solely impacted how proteins were made—now it appears that this basic assumption about reading the human genome missed half of the picture. New findings highlight that DNA is an incredibly powerful information storage device, which nature has fully exploited in unexpected ways. For example, DNA consists of a 64-letter (codon) alphabet that spells out the genetic code. The letters (codons) are organized into words and sentences called genes. About 15% of the 64-letter (codon) alphabet are dual-use letters known as duons. They simultaneously specify both amino acids and something called transcription factor (TF) sequences. This means that many DNA changes that appear to alter protein sequences may actually cause disease by disrupting gene control programs or even both mechanisms simultaneously. Enter misspellings—otherwise referred to as mutations. Part 3 tomorrow.