The discovery of nucleic acids.


Nucleic acids are one of the four major biomolecules that include carbohydrates, lipids and proteins.

  • In 1869, the Swiss physician and biologist Johannes Friedrich Miescher discovered nucleic acids when he isolated them from the nuclei of white blood cells.
  • First, he collected pus from used bandages in hospitals.
  • As pus is full of white blood cells, he washed the bandages with a dilute solution of sodium sulphate to collect the cells separately in a solution.
  • Once the cells were isolated, he rinsed the cells with dilute hydrochloric acid to separate the nuclei from the cytoplasm.
  • Then, he extracted the isolated nuclei with alkaline solutions and upon adding hydrochloric acid, a white precipitate formed.
  • He discovered that, unlike proteins, the precipitate did not contain sulphur and instead contained a large amount of phosphorous. Considering this, Miescher was the first to isolate deoxyribonucleic acid (DNA) and other nucleic acids.

Here is a photograph of Friedrich Miescher:

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