Causes of genetic mutations
The DNA is subjected to repeated attacks of chemical or physical environment of the cell agents substances can cause natural mutations.
But in addition to nature, there are also attacks produced by unhealthy social (alcohol, tobacco,...) and eating habits that have increased the number of mutagenic agents. These mutagenic agents can be classified into:
- Chemical mutagens: they are chemical compounds capable of abruptly altering DNA structures, such as:
- Alkylating agents, such as mustard gas, which alter replication by introducing radicals methyl, ethyl, ...
- Intercalating agents, such as acridine orange and benzopyrene. Benzopyrene that binds to DNA preventing base pairing.
- Deaminating agents.
- Analogs of puric and pyrimidine bases.
- Nitrous acid that accelerates the transformation of cytosine into uracil.
- Dioxins that are carcinogens.
- Physical mutagens: these are radiations that can alter the sequence and structure of DNA.
By derivative work: Mouagip (talk)DNA_UV_mutation.gif: NASA/David HerringThis vector graphics image was created with Adobe Illustrator. (DNA_UV_mutation.gif) [Public domain], via Wikimedia Commons
Vídeo: Radiación UV y mutación del ADN.
- Ionizing radiation (X-rays, gamma), break the phosphodiester bonds, altering the DNA chains. For example, gamma and alpha radiation. The ultrasound also produce structural chromosomal variations.
Biological mutagens: are those "living" organisms that can alter the sequences of the genetic material of their host, such as: viruses, bacteria and fungi. Examples are transposons (autonomous DNA fragments).
- Factors that are not mutagenic agents but that determine whether or not a mutation will take place: temperature, oxygen pressure, aging.
The 37 ºC of temperature causes, for example, that the human cells lose every day about 5000 puric bases (adenine and guanine) and the transformation of cytosine into uracil and adenine into hypoxanthine.
- Mutagens that result from metabolized non-carcinogenic substances, for example benzopyrene is the substance resulting from liver metabolism.