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Gregor Mendel publishes work on hereditary traits in peas. He notes that certain traits are passed from parent to offspring. Later these factors are called genes.
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Friedrich Miescher describes an acidic substance in a cell's nuclei. This substance, first called nuclein, is now identified as DNA.
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Thomas Hunt Morgan conducts experiments where he demonstrates that genes are located linearly along chromosomes.
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Frederick Griffith, in an experiment with mice, transfers the fatal component of a bacteria causing pneumonia to a benign strain of bacteria, which then cause a fatal pneumonia in the mice. He then determined that there must be a genetic factor that can transform the bacteria.
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Phoebus Levene discovers deoxyribose sugar in nucleic acids. Later on, demonstrates that DNA is made up of nucleotides, which are composed of a deoxyribose sugar, a phosphate group, and a base.
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William Astbury takes X-ray diffraction pictures of DNA.
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Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrate that it is not protein but DNA that is the factor that Frederick Griffith identified.
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Erwin Chargaff demonstrates that the bases of DNA are equal = there is an A for every T and a C for every G.
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Maurice Wilkins and Rosalind Franklin image DNA crystals via X-ray. These images are the basis for the conclusions of Watson and Crick.
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Various discoveries of individual genes for cystic fibrosis, Huntington's disease, etc. Also, genetically engineered food, and animal cloning.
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James Watson and Francis Crick publish their description of DNA. They describe it as a double-helix -two spirals held together by complementary base pairs.
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Announcement of a draft of the human genome by a joint venture of the public and a private company called Celera.
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Final completion of the human genome sequence announced.
