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Work with heredity and genes
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. -
Acid, not protein, in cell nuclei
Friedrich Miescher describes an acidic substance in a cell's nuclei. This substance, first called nuclein, is now identified as DNA. -
Linear genes discovered in chromosomes
Thomas Hunt Morgan conducts experiments where he demonstrates that genes are located linearly along chromosomes. -
Genetic factor in bacteria transferred
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. -
Components of DNA discovered
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. -
First pictures of DNA taken
William Astbury takes X-ray diffraction pictures of DNA. -
More proof for DNA in genes over proteins
Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrate that it is not protein but DNA that is the factor that Frederick Griffith identified. -
Base pairs discovered
Erwin Chargaff demonstrates that the bases of DNA are equal = there is an A for every T and a C for every G. -
DNA crystals photographed
Maurice Wilkins and Rosalind Franklin image DNA crystals via X-ray. These images are the basis for the conclusions of Watson and Crick. -
Period: to
Advances in genetics
Various discoveries of individual genes for cystic fibrosis, Huntington's disease, etc. Also, genetically engineered food, and animal cloning. -
Watson and Crick describe double-helix DNA
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. -
Human genome project announced
Announcement of a draft of the human genome by a joint venture of the public and a private company called Celera. -
Human genome complete
Final completion of the human genome sequence announced.
