The discovery of the double-helical structure of DNA was one of the most prolific breakthroughs of the 20th Century, as we were finally able to explain how genetic information was stored, copied, and passed down through generations. Before this, scientists knew of trait inheritance, but could not fully understand the physical mechanisms behind it. Throughout the middle of the century, the work of James Watson and Francis Crick (and Rosalind Franklin) showed DNA is shaped as a twisted ladder. This find answered a wealth of questions nagging the scientific community. Firstly, it explained how so much hereditary information could be stored in such a stable yet compact space as inside cellular nuclei. Knowing the structure is comprised of base-pairs, we understand more clearly how DNA replication works; that the unzipping and copying of a strand is how trait information gets passed on. Second, it also shed light on why mutations happen and how evolution can occur through these changes over time.
DNA research has created numerous possibilities in the fields of medicine, biology, and technology. As scientists could now study genes directly, they could identify inherited diseases, provide forensic DNA testing, and it made possible the human genome project. A breakthrough in itself, Kary Mullis pioneered the use of PCR, allowing researchers to make millions of copies of DNA very quickly, dramatically speeding up the time it takes to analyze genetic material. Once a painstaking process, this new replication method was also more inexpensive and reliable, allowing for widespread use in criminal investigations, paternity testing, and detecting and diagnosing genetic disorders and diseases. Overall, the discovery of DNA’s structure helped morph the field of Biology from a primarily observational science into a molecular one, allowing us to answer how heredity works, and providing new tools which continue to shape the research in many fields to this day.