How DNA Can Mutate
DNA is coded by four nucleotides: (A) adenine, (G) guanine, (T) thymine, and (C) cytosine. When three of these nucleotides are read at a time, called a reading frame, they code for an amino acid. Amino acids then go on to build proteins which are an essential building block of life. Sometimes when coding for amino acids our bodies make mistakes or some outside factors cause us to miscode for our proteins, which can lead to many problems like tumors and diseases.
The first type of mutation is called a point mutation and it is the simplest form of mutation to fix. There are two types of point mutations: indel and base substitutions. Indel, which means insertion and deletion mutations, either add or delete a nucleotide which cause a shift in the reading frame which leads to the wrong proteins being coded. The second type of mutation is a base substitution which can also be divided into two categories: transitions and transversions. A transition is when a base gets replaced by a base of the same category (either purine or pyramidine). Transversion is when a base gets replaced by a base of a different category.
Gene mutation can either be spontaneous or induced by an outside force. Spontaneous mutations are caused by replication errors (point mutations), depurination (the loss of a purine base), deamination (causing cytosine to turn into uracil) and oxidatively damaged bases caused be free radicals in a cell that can alter nitrogenous bases and cause mispairing. Induced mutations are caused by mutagens. Exposure to mutagens is called mutagenesis and is a heavily researched part of a science. Some mutagens can cause specific base mispairing by modifying agents that change the chemical structure of the bases which result in mispairing which leads to a malfunctioning protein. Two mutagens that do this are EMS and NG. Intercalating agents cause the insertion or deletion of entire base pairs which leads to a frameshift mutation. Two mutagens that do this are Proflavin and Agent Orange. Base analogs are chemical compounds that act like normal bases but when they bind they act chemically different and pair with different bases than they normally would. An example of this type of mutagen is 2-AP. Through these very different ways of mutating our DNA, we can either look for cures to a wide array of diseases and these area of research is expanding at a very fast rate.