The Relationship between Genes and DNA - Essay Example

The polypeptide created as a result of the translation of the changed mRNA will carry a different sequence of amino acids. The function of the protein made by this polypeptide will be changed or lost as well (Blamire,2000). To put it in simpler language, mutation alters the function of the enzyme that catalyzes a particular gene function resulting in the change of inherited characteristics through different generations. It results in the alteration of DNA sequence and consequently results in changes in the genetic and physical appearance of an organism. Thus the phenotype of the organism carrying the DNA which went through mutation will be changed.

The agents which cause DNA mutation are termed mutagens. These can be either physical agents or chemical ones (Matulef 2004). There are specific chemical mutagens created and calibrated to create specific genetic changes. They can either mimic the original nucleotide bases in a DNA molecule or remove parts of the nucleotide resulting in improper base pairing during DNA replication. They can also cause genetic changes by adding hydrocarbons to various nucleotides. High energy radiations can also alter the DNA molecule and cause mutation (Matulef 2004). The ultraviolet radiation from the sun is another cause of the same. Ultraviolet rays in the presence of sunlight gamma rays and such ionizing radiation etc can increase the frequency of mutation above the natural level. Much differently from these kinds of mutagen-induced ones, mutations can also occur spontaneously.

The mutation may arise on account of different reasons. In a chromatid, the DNA helix runs continuously from one end to another in a highly supercoiled form. Therefore loss or gain (deletion or insertion/duplication) of a segment of DNA results in alteration in chromosomes (Monteleone, 1998) Since genes are located in chromosomes such an alteration may result in abnormalities or aberrations. Chromosomal aberrations are commonly seen in cancer cells. Moreover, Mutation may also arise due to changes in a single base pair of DNA. This is commonly known as a point mutation. A classic example of this is sickle cell anemia UHCC (1999).

It is classified into three types based on what erroneous codon code is for. They include Silent mutations, Missense mutations, and Nonsense mutations. In addition to that it could also be due to frameshift mutation where the DNA base pairs are either inserted or deleted. Hypercholesterolemia is an apt example of this type of mutation (Monteleone, 1998) It could also be beneficial as this is responsible for the creation of nylonase. As far as the type of mutation is concerned, they include; base pair substitutions and Frameshift mutations. The latter includes the inclusion or deletion of one or more nucleotides in the coding region of a gene. The former is much more complex including transitions and transversions (Monteleone, 1998) Read More