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1866 : Discovery that certain characteristics are inherited. Gregor Mendel carried out experiments on peas. He observed that characteristics such as height and colour are passed on from parents to their offspring. He noticed that: 1. Characteristics in plants were determnined by hereditary units (now called genes). 2. Hereditary units are passed on from both parents, one unit from each. 3. Hereditary units are dominant or recessive.
1869 : Nuclein discovered Friedrich Miescher discovered that there is an acidic substance present in the nucleus of a cell. This is DNA.
1944 : Genes can be transferred from one generation to the next Oswald Avery transferred DNA between bacteria. This passed the ability to cause disease from one strain of bacteria to another. These bacteria passed the trait on to their offspring. This showed that genes are made up of DNA.
1950 : DNA base pairs discovered Erwin Chargaff found out that, even though different organisms have different amounts of DNA, all DNA contains equal quantities of adenine and thymine, and of cytosine and guanine.
1952 : DNA crystals photographed
1953 : Double-helix structure of DNA identified James Watson and Francis Crick published their description of DNA. They described it as a double helix - two spirals held together by complementary base pairs.
1953 - 2000 :
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