Genetic Mutations Essay, Research Paper
What is a mutation? A mutation as defined by the dictionary is a sudden change in a heritable characteristic. There a several things that can cause a mutation in someone\’s or something\’s body. A genetic mutation is what causes mutations in an animal or human. To understand what a genetic mutation is and why it occurs, you would have to first understand the basics of DNA, including its structure. However since not everybody has the time to study DNA to learn about genetic mutations, I will try to break it down and explain genetic mutations as thoroughly as possible.
First I will give you a little background on the history of genetic mutations. Genetic mutations were first reported in 1901 by Hugo De Vries, a Dutch botanist. In 1929 an American biologist named Hermann Joseph Muller discovered that the rate of genetic mutations can be increases by X rays. Later it was discovered that other forms of radiation, high temperatures, and various chemicals also caused mutations. Another cause of genetic mutation that has been discovered is inbreeding. An example of inbreeding is when a cousin and another cousin have a child.
Next I will try to explain how DNA is structured. The backbone of the DNA chain is composed of alternating sugar and phosphate groups. In each sugar group there is one of four nitrogenous bases, adenine (A), guanine (G), thymine (T), or cytosine (C). Each DNA molecule is made up of two chains which are linked together by bonds between the bases of one chain and another. An A base is always bonded to a T, and every G base is paired with a C. The way the bases are arranged determines the genetic code of an organism. The genetic code then directs the synthesis of proteins at a cellular level, it is written in units called codons. Each codon specifies a particular amino acid. Each codon is made up of a sequence of three bases, for example you can have GAG, or TCA. The four different bases (A,G,T,and C) can be arranged into sixty-four different codons. Most amino acids are specified by more than one codon because proteins are built from only twenty amino acids.
A genetic mutation occurs when one base is substituted for another, or when one or more bases are placed or removed from a gene. A mutation as a result of a substitution of a gene for another affect only one codon, and the affects are usually not too severe. Although mutations caused by substitution is sometimes harmless, it does not mean that all substitution mutations are harmless, some are more severe than others. For example, the protein hemoglobin, which is an important component of red blood cells, is made up of hundreds of amino acids. If one of those amino acids is substituted for another, it could cause hemoglobin that forms an abnormal sickle shape. If a person inherits the mutation of an amino acid in hemoglobin, it will result in the disease sickle-cell anemia. Another form of a mutation is base insertions and deletions, this mutation alters the entire gene. When this occurs it changes every codon from the mutation location to the end of the gene. For example, make believe that the end of a gene reads ATG GGC ATA ACG ATT. If an extra A is added to the gene it changes the entire gene, it would read AAT GGG CAT AAC GAT T. Since the addition of one base affects many codons, a base insertion may have severe results.
Mutations that occur in humans and other animals that reproduce sexually can be divided into two types of mutations, somatic and germinal. Somatic mutations affect the body\’s cells, instead of the sex cells. Such mutations can produce a localized mutation, such as a white streak in a persons hair which should not be there. This mutation can not be passes onto offspring. Germinal mutations affect the sex cells, such as the eggs or sperm. Germinal mutations can be transmitted to the persons offspring. Many germinal mutations are usually harmful, many genetic diseases are a result of germinal mutation.
Genetic mutations can alter the life styles of humans and creatures greatly. Take for example a frog that has an ingrown leg attached to his body. An extra piece of a leg can disable a frog from being able to hop away from an enemy attempting to eat it. Another way genetic mutations can affect a persons life is if a person has a mutated body part. If a child has an ingrown finger for example, this can cause a lot of emotional damage. People fear what they do not understand, when children see a child with a mutation, they begin to tease that child, they call the child names and treat them as an outcast. When this happens to a child it can permanently scar a child, leading to having the child drop out from school and become a junkie. Another thing that could affect a persons life is if the person is born without a thumb. Since the thumb is what separates humans from animals, along with many other things, missing a thumb will prevent a person from doing many things. Without a thumb a person can not pick up a glass of water with one hand, nor can he hold a pencil to write a perfect essay on genetic mutations, like the one you are reading right now. A genetic mutattion can sometimes affect a person greatly, but sometimes, the person is not affected at all. A person is usually not affected too much when the mutation is very subtle, like a streak of white in a persons hair.
Genetic mutations are a very serious matter. Until I wrote this essay I had no idea how easy it is for a mutation to occur. All that needs to happen for a mutation to occur is an addition of deletion of one single base. The addition of a base will completely alter the gene and cause it to produce the wrong or incorrect amino acids. Although genetic mutations is a serious matter, many times the mutated gene can be masked by a dominate gene.