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Inheritance - Gregor Mendel
An experiment he conducted on pea plants brought about the idea that characteristics can be transferred from one generation to another of the same species. He didn't know what was responsible for this but noticed that offsprings carried particular characteristics in preference to another. So he concluded that traits could be dorminant or recessive. -
The Unique DNA molecule - Friedrich Meischer
Scientist pondered over the means for transferring inherited information. They finally accepted chromosomes as the means when they saw how they duplicated and mov during cell division. Meischer isolated different phosphate-rich chemicals which he referred to as nuclein from the nuclei of white blood cells in 1869. This let to the identification of DNA as the carrier of inherited traits. -
DNA in transmitting traits - Oswald Avery
Oswald Avery along with his colleagues, Colin McLeod & Maclyn McCarty elaborated on the Grififth's experiment of bacterial transformation which led to the discovery of DNA as the material of which chromosomes were made. -
Proof of DNA - Erwin Chargaff
Chargaff propounded 2 rules, stating that the DNA of any cell of any organism should have an equal ratio of purine & pyrimidine bases and that guanine and cytosine have equal amounts as do adenine and thymine. -
Path to discovery - Rosalind Franklin and Maurice Wilkins
Maurice & Franklin both worked on X-ray crystallography of DNA but due to unresolved reasons, they parted ways, developing an intense rivalry between them. She strived to eliminate misleading possibilities, so she worked out the positions of the groups in the DNA molecule relative to each other and the distances between them. This led her to build a 2-stranded helix model for the structure of the DNA. Their effort was significant to DNA modelling. -
Understanding the structure - James Watson & Franklin Crick
James & Francis put together a model to show the DNA structure based on the information collected from Rosalind Franklin and other scientific contributions to the structure of DNA. Watson discovered that 2 purines would be too small to be held by hydrogen bonds and 2 pyrimidines would be too big.
