* Friedrich Miescher (1869): He first isolated a substance from the nuclei of white blood cells, which he called "nuclein". This substance later became known as DNA.
* Phoebus Levene (1919-1930s): He identified the basic building blocks of DNA (nucleotides), determined their order, and proposed the tetranucleotide hypothesis, which incorrectly suggested that DNA was a simple repeating sequence.
* Oswald Avery, Colin MacLeod, and Maclyn McCarty (1944): They showed conclusively that DNA, not protein, is the genetic material in bacteria. This was a major breakthrough.
* Erwin Chargaff (1950): He discovered the base pairing rules (A=T, C=G), which proved crucial for understanding DNA's structure.
* Rosalind Franklin (1952): Using X-ray diffraction, she captured the first clear images of DNA's structure. Her photo 51 was instrumental in the discovery of the double helix.
* James Watson and Francis Crick (1953): They built the first accurate model of the DNA double helix, using Chargaff's rules and Franklin's X-ray diffraction data. This discovery was a landmark moment in science.
It's important to remember that the discovery of DNA was a process involving many scientists who built upon each other's work. While Watson and Crick are often credited with the discovery of the double helix, it's important to acknowledge the crucial contributions of those who came before them.
