December 17, 2024

Sydney Pastor 

12th Grade

Pine Crest School

DNA was first discovered by Swiss biochemist Friedrich Miescher in 1869. He denoted DNA as “nuclein” when he first discovered it by primarily isolating the component from the nuclei of white blood cells. Prior to Miescher's discovery, various scientists believed that proteins held genetic material due to their abundance within the body. Additionally, many scientists understood that proteins were made up of different amino acids and thought that this translated into the fact that they hold a plethora of genetic material. Miescher discovered DNA by accident. The biochemist’s primary goal was to study the protein components of leukocytes, however he ended up discovering something that would alter the scientific community forever.

First, Miescher utilized leukocytes from pus collected from discarded surgical bandages. Then, he treated the bandages to wash off the pus and utilized a saline solution to isolate the white blood cells from all other cellular components. To investigate inside the leukocytes, Miescher used varying alkaline solutions in order to dissolve the cellular membranes of the leukocytes. However, when he encountered a substance from the cell nuclei with chemical properties different from those of other previously studied proteins, Miescher became intrigued, knowing that he had discovered a new type of substance that was never before isolated.

Within the Twentieth century, another world renowned biochemist by the name of Phoebus Levene began further investigating Miescher's prior findings. He started by looking at the nuclein molecule's chemical makeup, which had yet to be done. Levene was the first person to discover the carbohydrate component of both DNA and RNA. Additionally, Levene identified the specific way in which DNA and RNA molecules combine throughout the body. Levene's polynucleotide model creation significantly aided scientists' understanding of genetic material. To create his polynucleotide model, Levene used the process of hydrolysis to break down nucleic acids found in yeast. As a result of his various experiments, Levene denoted that DNA was composed of a linkage of nucleotides. In addition to his polynucleotide model, Levene proposed that nucleotides are linked in a tetranucleotide structure.

Another key biochemical researcher who helped investigate the structural components of genetic material is Oswald Avery. Around 1913, Avery's famous hypothesis came to fruition. He hypothesized that the polysaccharides in the capsules were antigens that stimulate the production of antibodies within patients infected with pneumococcus bacterium. This hypothesis stemmed from the idea that antigens can stimulate antibody production within those who are infected.

These three, world-renowned, biochemical researchers significantly aided with the solidification of our knowledge surrounding both the origin and structural makeup of genetic material. These biochemical discoveries have led to developments in both immunology as well as microbiology.