In everyday life a person gets exposed to a number ofcompounds or materials which cause damage to the DNA causing mutations whichmay lead to cancer. This simply means Genotoxins affect the integrity of theDNA. Genotoxins are those compounds having a property of genotoxicity. Effectsof genotoxicity are most commonly being of 3 types. 1) Carcinogenic effects 2)Mutagenic effects 3) Teratogenic effects.
Carcinogens are cancer causing,mutagens are mutation causing, teratogens are birth defect causing compounds oragents. Majority of genotoxins are mutagenic in nature. All mutagens aregenotoxic but not all genotoxins are mutagenic. Every cell has a property ofDNA repair but when cell fails to repair then these compounds leads togenotoxicity in the cell. Generally, by the process of apoptosis or DNA repairgenotoxic mutations are avoided by all cells but these mutations get expressedwhen exposure to the genotoxic compound is frequent or continuous. It is notsure that a damage caused will always be fixed. So, a DNA damage that cannot befixed causes mutation or other genotoxic effects.
Genotoxicity can be on bothsomatic as well as on germ cells. If genotoxins affect somatic cells then itmay lead to cancer or cardiovascular diseases but if genotoxins affect germcell then they can cause genetic diseases like cystic fibrosis, sickle cellanemia or Haemophilia and multifactorial diseases like Psychosis,cardiovascular diseases and diabetes. These genetic diseases are inheritable tonext generation. When integrity of the DNA is damaged then it leads to causecancer in the body. A number of techniques have been developed to check thepotential of a chemical compound to cause genotoxicity like Ames test, Comettest and various in vitro in vivo toxicology tests. Ames test is a very a verycommonly used test to determine the genotoxicity of a compound using abacterium. It is very popular test because of its quick results while many oldstandard tests usually take about two to three years to complete.
Ames test isa quick alternative for these tests. Comet test is an alternative name of cometassay is SCGE (Single cell gel electrophoresis assay). Comet test detects theDNA damage at individual eukaryotic cell level.
It is a very simple and quickto detect and is most commonly employed technique. Micronucleus test is the oneof the most reliable assays which are recognized at present. It has twoversions of this test. 1) In Vivo 2) In Vitro. In vivo experiments areperformed on live animals while in vitro experiments are performed on cells andmicroorganisms. This type of experiments is commonly called as test tubeexperiments.
Genotoxin simply means any substance which is toxic to the genome.