Genetic Mutations: Examples and definition

Mutations are Hereditary variations in the genetic code. It is a structural change in one or more nucleotides that encode the genetic information of DNA. They can also be structural changes in a chromosome.

The mutations They occur spontaneously. Some occur with a frequency of one to ten thousand, being not so stable, but there are other genes that have managed to spend millions without modifying. They can be presented by:

• Exposure to ionizing radiation: like X -rays.
• For chemical substances: mainly that produce DNA alkylation.

These errors can occur when the DNA copy is made. When the error is large, the cell dies. If it is not so serious, the cell lives but it has malfunction. This mutation is transmitted from stem cells to daughter cells.

The mutation It is not always badIt can be beneficial too. This depends on the phenotypic changes that improve or deteriorate the survival capacity of the individual and the conditions that prevail in the environment before which they have to respond. These affects that affect are known as lethal mutations or alleles.

There are cases where mutations will be useful against rapid changes in the future in the futureto what It is called preadaptation. This is the case, for example, of the reptiles that separated from the amphibians when independence from water.

In addition to the term mutation, there are polymorphisms. These are minimal variations that give variability to the population and are a consequence of DNA mutations. They differ between them by the following:

• Mutation: They are genomic variations with less than 1%, and occurs in a particular organism.
• Polymorphism: variations with frequency more than 1%, and occurs in variations within a population.

Here are how genetic mutations are classified.

Structurally the most common genetic mutations can be of three different types. We can talk about:

• Deletions: where genetic material is erased and lost.
• Insertions: New fragments of genetic material are introduced.
• Substitutions: A genetic material is replaced by another.

At the same time, another of the classifications of genetic mutations can be done according to the consequences in the sequence of a protein. These variations are classified as:

• Silent variations: A nucleotide is modified but encodes for the same amino acid.
• Missense or misconception variations: There is a nucleotide change that changes to an amino acid.
• Variations nense or meaningless: Nucleotides are changed that will encode a term codon, leaving incomplete protein.
• Regulatory variations: Genes have sections that do not encode, but regulate genetic expression such as silencers, promoters, transcription factors. Even when a gene is not mutated, if your regulators are cannot be expressed correctly.
• Intronic variations: These modifications occur in DNA areas that do not encode for any protein. For this reason they will not manifest as diseases.
• Frameshift or Change of the Reading Frame: A base is introduced or eliminated that will displace the entire sequence and change the meaning of codon reading. This occurs because the base pairs must be in multiples of three, but the insertion of one displaces the sequence.
• Splicing: Modifications are created in introns near exons, which have regulatory function for the production of immature messenger RNA.

Mutations can generate malfunctions in organisms and derive in multiple diseases. Some examples of more common genetic mutations that have resulted in diseases are the following.

Amyotrophic lateral sclerosis

This disease is a failure the nervous system that causes degenerative paralysisas well as spinal cord sclerosis. This does not interfere in intelligence of individuals, as is the example of Stephen Hawking, an important theoretical physicist about relativity.

The genes involved in the fault can be caused, or those of genetic susceptibility, which are those that increase the possibility of obtaining the disease. Although the Causes are inheritable and cause the Family elabut only 10% of cases are like that.

On the other hand, It can be sporadic Because of the genes that increase susceptibility and interaction with the environment. This is 90% of caseswhich can manifest by:

• Oxidative stress
• Mitochondrial dysfunction
• Glutamate accumulation in nerve cells
• Exposure to cyanobacteria

This is a great example of how the environment has an effect on our genes.

Diabetes and Maternal inheritance (MIDD)

This type of diabetes occurs by a Mutation in mitochondria And sometimes in The insulin gene. It is inherited from mothers with said genetic disorder and manifests itself with defects in insulin secretion, deafness, dizziness, kidney diseases and heart problems. It is a type of monogenic diabetes, the result of mutation in a single gene.

If you want to know more about the mitochondria: function and structure, do not hesitate to consult this article that we suggest.

Family hypercholesterolemia

Occurs by one Mutation on chromosome 19which can happen for more than 1,600 different mutations in said chromosome. It is one Common hereditary disease and it is estimated that 1 in every 250 people have it. There is a 50% chance that the affected father transmits it to his children. It has the effect of bad cholesterol levels, or LDL, very high. This causes heart attacks at an early age.

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