Mutagens are external influences that trigger gene mutations or chromosome aberrations , i.e. change the genome of an organism. A distinction is made between physical mutagens such as radiation and high temperatures, chemical mutagens such as B. nitrosamines and polycyclic aromatic hydrocarbons and biological mutagens such. B. HP viruses and Epstein-Barr viruses. The ability to induce mutations is known as mutagenicity , sometimes with reference to an organ such as e.g. B. Germ cell mutagenicity .
Mutagens lead to a mutation via DNA damage . The normal mutation rate (frequency with which one or more genes change) in higher organisms is 10 −5 - 10 −9 per gene and generation. Mutagens cause this natural mutation rate to increase.
Well-known examples of mutagens are:
- Nitrosamines : arise, among other things, when deep-frying, roasting and grilling and in the stomach when digesting meat and cheese that have been preserved with nitrite curing salt , but also when consuming intensively fertilized plant-based foods. Change highly effective chemically the DNA - bases .
- Base analogues: Base-like substances are incorrectly incorporated into the DNA during replication and thus cause a change in the original sequence.
- Polycyclic aromatic hydrocarbons: push themselves between the bases and lead to grid mutations as a variant of the gene mutations . The process of storage in the DNA is called intercalation . A typical example is ethidium bromide , which is used in molecular biological laboratory technology for the specific detection of nucleic acids, among other things. The ethidium bromide molecules store themselves in the base sequence with the formation of π-stack interactions , which can cause a shift in the reading frame.
- many other chemical substances such as: arsenic acid and its salts, asbestos , benzene , acrylamide , benzopyrene , cobalt chloride , petrol , crude oil
- Aflatoxins : highly toxic and by binding to DNA - bases carcinogenic product of various molds.
- High- energy radiation: X-rays , ionizing and UV radiation cause mutations and chromosome aberrations.
- Some tumor viruses : HI viruses, Epstein-Barr viruses, and HP viruses
The Ames test is one of the simplest and most common tests used to determine a chemical as a mutagen.
Categories according to the CLP regulation
According to the CLP regulation , substances can be classified in the hazard class "germ cell mutagenicity" with categories 1A, 1B and 2 due to their germ cell mutagenicity. Substances and mixtures of categories 1A and 1B are identified with the hazard pictogram "Health hazard" (GHS08) and the signal word "Danger", the H phrase H 340 and the corresponding P phrases. Category 2 substances and mixtures are labeled with the hazard pictogram "Health hazard" (GHS08) and the signal word "Caution", the H 341 and the corresponding P-phrases.
- Category 1A
Substances known to cause heritable mutations in human germ cells. The classification is based on positive findings from epidemiological studies on humans.
- Category 1B
Substances known to cause heritable mutations in human germ cells. This assumption is generally based on: suitable long-term animal studies, other relevant information.
- Category 2
Substances that can trigger hereditary mutations in human germ cells. Some evidence is available from suitable animal experiments, but this is not sufficient to classify a substance in Category 1.
- Radiation biology
- Radiation sickness
- Category: Mutagenic Substance (List of substances available in Wikipedia, classified as H340 or H341)