8 Types of DNA Mutations and Their Potential Impacts
There are a number of ways the DNA sequence in a gene can be altered. These alterations can have various effects on the body depending on where they occur, and in the process, they may alter the essential functions of the protein. Here are 8 types of DNA mutations and their potential impacts.
Type 1 – Missense Mutation
Missense mutation occurs when there is a change in one DNA base pair where one amino acid is substituted with another. This alteration can cause the resulting gene to malfunction or continue to function depending on the type of amino acid it is substituted with. Such mutations are responsible for Sickle Cell Anemia, which occurs when one nucleotide of the gene from the beta chain for hemoglobin is altered.
Type 2 – Nonsense Mutation
A nonsense mutation occurs when a DNA base pair changes into one instead of substituting one amino acid with another. According to CRI Genetics, the DNA sequence abruptly signals the cell to stop building a protein. This leads to a thwarted incomplete protein product. When this mutation occurs, the resulting protein may either lose its function completely or function improperly depending on where in the sequence the stop occurred. This leads to a loss of genetic information in a particular gene.
Type 3 – Insertion Mutations
These types of DNA mutation occur when one or more nucleotide base pairs are added onto a DNA sequence. As a result, the gene may function improperly due to the addition of genetic information. The size of the insertions varies in size, from a single DNA base pair to an entire chromosome adding onto another. Insertion mutations can be harmful when the addition occurs in the amino acid coding region of a gene, making the resulting sequence lose its intended function.
Type 4 – Deletion Mutation
As the name suggests, in this is a type of mutation, an entire chromosome or DNA sequence is lost during a DNA’s replication. This leads to the improper functioning of the resulting proteins due to the loss of genetic information. Deletions that do not occur in multiples of three bases cause a frameshift by changing the 3-nucleotide protein reading frame of the sequence. One of the common diseases caused by this mutation is Cystic Fibrosis.
Type 5 – Inversion Mutation
This type of mutation occurs when there is breakage and rearrangement of the chromosome within itself. The broken chromosome reverses and reattaches itself, inverting the order in which the reading frame is aligned. No DNA is lost in the process; the only change being the realignment. In most cases, there is none or minimal change in a gene’s functionality. However, in a number of cases, some have suspected that this mutation leads to increased risks of miscarriages and infertility.
Type 6 – Duplication Mutation
This mutation happens when a section of a chromosome or gene duplicates itself, causing an increase in genes dosage in that particular region. This can be a result of several DNA errors as well as repair mechanisms. Some of the common causes of this mutation are retrotransposition events, ectopic recombination, replication slippage and polyploidy. This mutation is known to cause some types of cancer due to the replication of the genes.
Type 7 – Translocation Mutation
This type of DNA mutation occurs when a segment of a chromosome breaks off and attaches itself to a completely different chromosome. Translocation mutations can either be balanced or unbalanced. A balanced translocation occurs when the newly attached chromosome does not cause any loss or gain in genetic information, while an unbalanced translocation happens when the newly attached chromosome leads to loss of information or addition of extra genetic information. This mutation causes a form of Leukemia, mantle cell lymphoma and follicular thyroid cancer.
Type 8 – Frameshift Mutation
This mutation occurs when the addition or loss of DNA bases cause a change in the genes reading frame. Reading frames consist of three bases that together form the code for an amino acid.
Once the mutation occurs and causes a change in the reading frame, the code for the amino acids changes as well, leading to the creation of dysfunctional proteins. This mutation is evident in severe genetic complications such as Tay-Sachs disease. Frameshift mutations are also caused when there are insertions, deletions and duplication of the DNA bases in a gene.
DNA mutations cause many unforeseen changes in gene structures, which in turn lead to a number of physical health problems if the resulting mutations are harmful. It is also important to note that DNA mutations have led to the evolution of life as we know it.
The different types of DNA mutations are attributed to various diseases since they destabilize and distort the normal order of a gene. These distortions and imbalances can wreak havoc in your body and cause it to react in ways that activate various types of diseases such as cancer, among others. It’s however important to note that not every mutation is harmful.