The Origins of Research on the Genetic Code Flashcards
DNA was actually first observed in the 1800s by a Swiss scientist called Fr
Friedrich Miescher
However, many scientific researchers at that time doubted that this newly discovered DNA molecule could carry the genetic code
They doubted this because of the
relatively simple chemical composition of DNA (because DNA was only made up of simple repeating nucleotides, which themselves were only composed of three parts: a phosphate group, deoxyribose, a nitrogen-containing organic base
For example, some scientists hypothesised that genetic information must be carried by
proteins, which show much higher levels of chemical complexity
For example, proteins are which are made up of 20 different amino acids whereas DNA is made up of only 4 different nucleotides
As a result, it wasn’t until the 1940s that the role of DNA in genetic inheritance began to be more fully researched and understood
By 1953, experiments had confirmed that DNA carried the genetic code
It was understood that, despite there being only 4 nucleotides, the use of the
triplet code enabled much variation (the code is universal and degenerate)
The location of DNA, protected in the nucleus, enabled
the security of the genetic material rather than proteins that are found in the cytoplasm and susceptible to hydrolysis
DNA is easily copied and therefore conserved throughout generations of cells and inherited between generations within families
1953 was also the year in which Watson and Crick confirmed the double-helix structure of DNA using
Rosalind Franklin’s X-ray data
Don’t worry about learning the dates or names given above - the main point you need to remember here is that the relative simplicity of DNA led many scientists to doubt that it carried the genetic code and that this is perhaps why the function of DNA wasn’t confirmed until a relatively long time after its initial discovery
