The 1920s was a time of great prosperity in the United States; advancements were made in many areas of life. The field of genetics also saw many groundbreaking discoveries. The research of scientists such as Thomas Hunt Morgan and Hermann Joseph Muller proved the existence of chromosomes and genes as well as showed how mutations can be influenced and passed on to offspring. Geneticists from this decade used their study results to form a more complete understanding of previously constructed theories. Genetic research of the 1920s significantly advanced scientific thinking and understanding regarding heredity and evolution of species. As a professor of biology at Columbia University, Thomas Hunt Morgan, along with his colleagues, used his
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Fredrick Griffith’s 1928 experiments with Streptococcus pneumoniae demonstrated that an unknown component, later found to be DNA, existed inside every living being and had the power to pass on its genetic material to other organisms (“1920s Timeline” 14). In his experiments, Griffith injected groups of mice with different versions of the pneumonia-inducing bacteria. One such strain (strain S), which he observed as encapsulated and having a smooth outer surface, was known to be lethal to mice unless killed under very high temperatures, in which case it would no longer be virulent. Conversely, another strain (strain R) had a rough surface and was nontoxic to mice. In a third group of mice, Griffith injected a mixture of the heat-killed S strain and the live R strain; these mice developed pneumonia and died. Bacteria collected from the third group of mice was of the live S strain (Farabee). Griffith’s discoveries showed that genetic material of a dead virulent bacteria could be passed to a live non-toxic strain and transform the latter into live virulent bacteria (“1920s Timeline” 14). Several decades later this would later be recognized as a transfer of
Fredrick Griffith’s 1928 experiments with Streptococcus pneumoniae demonstrated that an unknown component, later found to be DNA, existed inside every living being and had the power to pass on its genetic material to other organisms (“1920s Timeline” 14). In his experiments, Griffith injected groups of mice with different versions of the pneumonia-inducing bacteria. One such strain (strain S), which he observed as encapsulated and having a smooth outer surface, was known to be lethal to mice unless killed under very high temperatures, in which case it would no longer be virulent. Conversely, another strain (strain R) had a rough surface and was nontoxic to mice. In a third group of mice, Griffith injected a mixture of the heat-killed S strain and the live R strain; these mice developed pneumonia and died. Bacteria collected from the third group of mice was of the live S strain (Farabee). Griffith’s discoveries showed that genetic material of a dead virulent bacteria could be passed to a live non-toxic strain and transform the latter into live virulent bacteria (“1920s Timeline” 14). Several decades later this would later be recognized as a transfer of