What is the Difference Between DNA Damage and Mutation

The main difference between DNA damage and mutation is that DNA damage is a structural change in DNA whereas mutation is a change in the nucleotide sequence of DNA. Furthermore, DNA damage prevents DNA replication while mutation alters the genetic information encoded by DNA. 

DNA damage and mutation are two groups of errors that occur in DNA. Moreover, environmental factors, as well as the compounds released by metabolism, can cause DNA damage while mutations mainly arise due to the errors in DNA replication and recombination. 

Key Areas Covered 

1. What is a DNA Damage
     – Definition, Causes, Types
2. What is a Mutation
     – Definition, Causes, Types
3. What are the Similarities Between DNA Damage and Mutation
     – Outline of Common Features
4. What is the Difference Between DNA Damage and Mutation
     – Comparison of Key Differences

Key Terms 

Chemical Changes, DNA Damage, Frameshift Mutations Mutation, Point Mutations, Strand Breaks

What is a DNA Damage 

DNA damage is a type of error in DNA, bringing structural changes to the DNA. The main importance of DNA damage is that it has the ability to prevent the functioning of DNA replication. However, most DNA damages undergo DNA repair, which is not 100% efficient. However, the accumulation of un-repaired DNA damages in non-replicating cells, including brain cells and muscle cells, cause ageing. On the other hand, un-repaired DNA damages in replicating cells lead to mutations or epigenetic alterations.  

Figure 1: Effect of DNA Damage

Significantly, the damages in DNA can alter the function of genes or the regulation of gene expression, possibly contributing to cancer. Therefore, the G2 checkpoint checks for possible DNA damages along with the completion of DNA replication during the cell cycle before proceeding.

Figure 2: DNA Damage by UV

Furthermore, the three main types of DNA damages are the chemical changes of nitrogenous bases including O6-methylguanine and cytosine deamination, missing of bases including depurination and depyrimidination, and breaks in DNA strands. Also, DNA damages can occur naturally due to the compounds produced by the body during metabolism or hydrolytic processes. Reactive species of oxygen, nitrogen, and carbonyl, alkylating agents, and, lipid peroxidation products are examples of compounds which damage DNA. Moreover, environmental factors including ionization radiation, UV radiation, and genotoxic compounds can cause DNA damages. 

What is a Mutation 

A mutation is another type of errors in DNA which causes alterations in the nucleotide sequence. It mainly arises through the errors in DNA replication and recombination. Since a mutation can pass through generations, it is a type of permanent change in the DNA. Most mutations are harmless while some mutations can cause cancers or other lethal disease conditions.  

Figure 3: Point Mutations

Furthermore, the three main types of mutations are base substitutions, insertions, and deletions. The two main types of base substitutions are transitions and transversions. Here, transitions are the substitutions of purine by another purine or pyrimidine by another pyrimidine. Transversions are the substitutions of purine by a pyrimidine and vice versa. These base substitutions lead to point mutations, which can be either silent, missense or nonsense. Moreover, insertions and deletions are two types of frameshift mutations, which add or remove one or more bases respectively to or from the DNA strand.

Figure 4: Chromosome Structural Changes

However, large-scale mutations which bring alterations in the chromosome structure arise due to the damages in the DNA backbone.  

Similarities Between DNA Damage and Mutation 

• DNA damage and mutation are two types of biological consequences which bring changes to DNA. 
• They lead to alterations of gene function or the regulation of gene expression. 
• Also, the DNA repair mechanisms are responsible for correcting both types of changes in DNA. 
• However, some of these changes can lead to cancer and other disease conditions.  

Difference Between DNA Damage and Mutation 

Definition 

DNA damage refers to the injuries to DNA that introduce deviations from its normal, intact structure and which may if left unrepaired, result in a mutation or a block of DNA replication. A mutation refers to the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements. Thus, these definitions explain the main difference between DNA damage and mutation.

Significance 

Moreover, DNA damage is a structural change in DNA while a mutation is an alteration of the nucleotide sequence in DNA. 

Durability 

Durability is also an important difference between DNA damage and mutation. Most DNA damages are repaired by cellular mechanisms while mutations are permanent changes in DNA. 

Consequence 

Another difference between DNA damage and mutation is that un-repaired DNA damages become mutations in replicating cells while mutations pass over generations.  

Causes 

Compounds released during metabolism and environmental factors cause DNA damages while the errors in DNA replication and recombination cause mutations. Hence, this is a major difference between DNA damage and mutation.

Types 

The three types of DNA damages are the chemical changes of nitrogenous bases, missing of bases, and breaks in DNA strands while the three types of mutations are substitutions, deletions, and insertions. 

Importance 

Furthermore, one other difference between DNA damage and mutation is that DNA damages prevent the proceeding of DNA replication while mutations change the genetic information encoded by DNA.  

Conclusion 

DNA damage is a type of structural alteration in DNA, arising due to the compounds released by metabolism or due to environmental factors including radiation. But, most of the DNA damages are repaired by DNA repair mechanisms. The un-repaired DNA damages in replicating cells cause mutations in the chromosome structure. On the other hand, a mutation is a heritable change in the nucleotide sequence of DNA. It arises due to the errors in DNA replication and recombination. The two main types of mutations are point mutations and frameshift mutations. Therefore, the main difference between DNA damage and mutation is the type of change in DNA.

Reference:

1. “Types of DNA Damage & Causes of DNA Damage, Deamination Damage.” Cell Biolabs, Inc., Available Here
2. Sturm, Noel. DNA Mutation and Repair. California State University, Dominguez Hills Faculty, 2015, Available Here

Image Courtesy:

1. “DNA damage leads to Aging, Cancer or Apoptosis” By Bernstein0275 – Own work (CC BY-SA 4.0) via Commons Wikimedia  
2. “DNA UV mutation” By NASA/David Herring – NASA, [1] (Public Domain) via Commons Wikimedia  
3. “Different Types of Mutations” By Jonsta247 (CC BY-SA 4.0) via Commons Wikimedia    
4. “Chromosomes mutations-en” By GYassineMrabetTalk✉This W3C-unspecified vector image was created with Inkscape. – Own work based on Chromosomenmutationen.png (Public Domain) via Commons Wikimedia