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Identification of nuclein
Friedrich Miescher identified the “nuclein” by isolating a molecule from a cell nucleus that would later become known as DNA. -
Naming of DNA
Nobel Prize winner and German biochemist Albrecht Kossel, who is credited with naming DNA, identified nuclein as a nucleic acid. He also isolated those five nitrogen bases that are now considered to be the basic building blocks of DNA and RNA: adenine (A), cytosine (C), guanine (G), and thymine (T) (which is replaced by uracil (U) in RNA). -
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DNA is responsible for heredity
Erwin Chargaff discovered that DNA is responsible for heredity and that it varies between species. His discoveries, known as Chargaff’s Rules, proved that guanine and cytosine units, as well as adenine and thymine units, were the same in double-stranded DNA, and he also discovered that DNA varies among species -
Imaging DNA structure
Roslind Franklin’s work in X-ray crystallography began when she started taking X-ray diffraction photographs of DNA. Her images showed the helical form, which was confirmed by Watson and Crick nearly two years later. Her findings were only acknowledged posthumously. -
Watson and Crick double helix structure of DNA
Watson and Crick published on DNA’s double helix structure that twists to form the ladder-like structure we think of when we picture DNA.