What are mutations?
A mutation is a change in the structure of DNA. DNA is constantly undergoing chemical change in a cell, especially during replication. Most of these accidental changes are quickly repaired, but those that are not result in a mutation; thus, a mutation can be described as a failure to repair a miscopy of DNA. They happen randomly and spontaneously, and result in offspring which exhibit variations that do not resemble either of their parents and have never occurred in the family before. An organism which possesses a characteristic that results from mutation is known as a mutant. Most mutations are not harmful, and result in genetic variation, such as eye, hair and skin colour. However, sometimes mutation can be harmful and can result in an array of genetic disorders. Considering the millions of cell divisions that take place within an individual, mutations are quite rare. When they usually occur, they happen to the parts of our chromosomes which do not contain any coding information - introns - and thus have no effect on the individual. There are two types of mutations: gene mutations - occur during the replication of DNA molecules; and chromosomal mutation - occurs before birth and affects all parts of the chromosome.
However, there are agents that exist which increase the rate at which mutations occur - mutagens. It is important to note that mutagens do not cause defects - they simply increase the rate at which they occur. It creates a physical or chemical change to genetic material, thus increasing the frequency at which mutations occur. Some common forms of mutagens include mustard gas, formaldehyde and sulfur dioxide.
Not all mutations are harmful however. In rare cases, mutations can lead to new versions of proteins which help an individual better adapt to changes in their environment.
However, there are agents that exist which increase the rate at which mutations occur - mutagens. It is important to note that mutagens do not cause defects - they simply increase the rate at which they occur. It creates a physical or chemical change to genetic material, thus increasing the frequency at which mutations occur. Some common forms of mutagens include mustard gas, formaldehyde and sulfur dioxide.
Not all mutations are harmful however. In rare cases, mutations can lead to new versions of proteins which help an individual better adapt to changes in their environment.