Gene Mutation Type and Consequences

A gene mutation occurs when a gene’s DNA sequence is permanently changed. A DNA gene sequence can be altered in several different ways. These mutations range from a large chromosome segment to a single DNA building block. Gene mutations can be acquired during an individual’s lifetime or they can be inherited from an individual’s parent. Some gene mutations are quite common in the population, while other are very rare.

Missense Mutation

This gene mutation type results from a change in one DNA base pair. This causes one amino acid to be substituted for another in the gene-produced protein.

Insertion

This mutation involves the amount of gene DNA bases changes by a piece of DNA being added. This can result in the protein that the gene produces not functioning properly.

Duplication

This mutation involves a piece of DNA being copied one or more times abnormally. This can result in the resulting protein’s function being altered.

Repeat Expansion

Short DNA sequences, also referred to as nucleotide repeats, are repeated several times in a row. This gene mutation type increases how many times the nucleotide repeats is repeated. This can result in a protein that doesn’t function properly.

Frameshift Mutation

This mutation involves a gene’s reading frame changing due to the loss or addition of DNA bases. This results in the protein that results being nonfunctional. Deletions, duplications, and insertions can all be frameshift mutations.

Nonsense Mutation

This mutation is also a DNA base pair change. The DNA sequence that is altered prematurely tells the cell to halt the building of a protein, instead of substituting one amino acid for another amino acid. This mutation results in the protein that is shortened either not functioning at all or functioning improperly.

Deletion

This mutation removes a piece of DNA, resulting in the amount of DNA bases changing. Larger deletions can results in an entire gene being removed, or several neighboring genes being removed. A small deletion may result in one or a few gene base pairs being removed. When DNA is deleted, the resulting protein’s function can be altered.

Effects of Gene Mutations

When genes are mutated, they can have a variety of effects of health, depending on where the mutations occur and whether essential protein function is altered. Understanding gene mutation types helps doctors, scientists, and patients better understand how genes become mutated and what happens when they do become mutated.

Polymorphisms are responsible for the several different differences between individuals, such as hair color, eye color, and blood type. Polymorphism variations can have an impact on an individual’s risk of developing certain genetic disorders, but most polymorphisms do not have a negative impact on an individual’s health.

Resources

Genetics Home Reference. (2010). What Kinds of Gene Mutations are Possible? Retrieved on July 24, 2010 from Genetics Home Reference: https://ghr.nlm.nih.gov/handbook/mutationsanddisorders/possiblemutations

Berkeley University. (2010). Types of Mutations. Retrieved on July 24, 2010 from Berkeley University: https://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_03