What is the Difference Between Genotoxicity and Mutagenicity

The main difference between genotoxicity and mutagenicity is that genotoxicity is the ability of harmful substances to cause damage to genetic information, whereas mutagenicity is the changes in the amount and the structure of the genetic material.

Genotoxicity and mutagenicity are two types of changes that occur in genetic material. Both bring changes to genetic information.

Key Areas Covered

1. What is Genotoxicity
     – Definition, Agents, Importance
2. What is Mutagenicity
     – Definition, Agents, Importance
3. Similarities Between Genotoxicity and Mutagenicity
     – Outline of Common Features
4. Difference Between Genotoxicity and Mutagenicity
     – Comparison of Key Differences

Key Terms

Genotoxicity, Mutagenicity

What is Genotoxicity

Genotoxicity is the ability of harmful substances to cause damage to the genetic information of a cell. Generally, genotoxic substances include biological, physical, and chemical agents that cause damage to genetic material. However, they do not cause genetic alterations in the DNA sequence. Therefore, genotoxic substances are not usually mutagenic. Genotoxic substances cause damage to genetic material through direct and indirect interactions. On the other hand, major DNA repair pathways, including direct repair, nucleotide excision repair (NER), base excision repair (BER), and mismatch repair, can repair the damages caused by genotoxic substances to the genetic material.

Figure 1: Transversions

For example, chromium is a transition metal that interacts with DNA and causes damage to genetic material. Generally, the high-valent oxidation state of chromium causes lesions that contain G–>T transversions, and they are carcinogenic. However, genotoxic substances do not always associate with mutations. Nevertheless, the exposure of genetic material to genotoxic substances can induce genomic instability and epigenetic alterations that subsequently transfer into diseases, including cancer.

What is Mutagenicity

Mutagenicity is the induction of permanent transmissible changes in the amount and the structure of genetic material in organisms. Therefore, the main feature of mutagenicity is the induction of mutations. More importantly, errors during DNA replication, repair, and recombination can cause mutations. Generally, the main types of mutations include point mutations, gene mutations, chromosomal aberrations, and genome mutations. In addition, the agents that induce mutation are known as mutagens. The main types of mutagens are physical mutagens, DNA reactive chemicals, base analogs, intercalating agents, metals, and biological agents. Physical mutagens include UV radiation, ionization radiation like X-rays, radioactive decay, etc.

Figure 2: Mutations

Moreover, some DNA reactive chemicals include reactive oxygen species, deaminating agents like nitrous acid, and alkylating agents like nitrosamines, aromatic amines, benzene, bromine, sodium azide, etc. Base analogs like 5-bromouracil can also act as mutagens. Besides, intercalating agents like proflavine and ethidium bromide serve as mutagens. Nickel, cadmium, chromium, and arsenic-like metals are mutagens as well. Finally, biological agents, including transposons, bacteria, and viruses, can serve as mutagens, leading to changes in the nucleotide sequence.

Similarities Between Genotoxicity and Mutagenicity

• Genotoxicity and mutagenicity are two types of processes that make changes in the genetic material in organisms.
• External factors are involved in both processes.

Difference Between Genotoxicity and Mutagenicity

Definition

Genotoxicity refers to the ability of harmful substances to damage genetic information in cells while mutagenicity refers to the induction of permanent transmissible changes in the amount or structure of the genetic material of cells or organisms.

Correspondence

Not all genotoxic substances are mutagenic, while all mutagenic substances are genotoxic.

Importance

Genotoxic substances cause harm to the genetic information of the cell, while mutagenic substances alter the structure and the amount of genetic material.

Results

Genotoxic substances result in epigenetic changes and genomic instability, while mutagenic substances result in mutations.

Transfer to Next Generation

The changes made by genotoxic substances do not transfer to the next generation, while the changes made by mutagenic substances transfer to the next generation.

Conclusion                                                                                          

In brief, genotoxicity and mutagenicity are two types of processes that make changes in the genetic material of organisms. Genotoxicity is the ability of harmful substances to cause damage to genetic information. Therefore, it brings epigenetic changes and genomic instability to genetic material. The changes made by genotoxic substances do not transfer to the next generation. In comparison, mutagenicity is the permanent transmissible changes that occur in the amount and the structure of the genetic material of cells. These changes cause mutations that pass to the next generation. Hence, the main difference between genotoxicity and mutagenicity is the type of changes that occur in the genetic material.                                                         

References:                

1. Ren, N., Atyah, M., Chen, WY. et al. The various aspects of genetic and epigenetic toxicology: testing methods and clinical applications. J Transl Med 15, 110 (2017). 

Image Courtesy:

1. “Transitions and transversions” By Krishnavedala – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Point mutations-en” By Jonsta247 – Own Work (CC BY-SA 4.0) via Commons Wikimedia