Mutagenic
agents
They are physical, chemical
and biological factors that cause mutations and increase the spontaneous
mutation rate. They act harming the composition or structure of DNA.Physical mutagens
- Ionizing radiation. They are radiation having very short-wave length and are therefore very energy, causing the loss of electrons in some atoms DNA remaining as highly reactive ions. They can cause breakage of chromosomes favoring the appearance of chromosomal mutations and produce modifications in the bases leading to the formation of point mutations.
- Non-ionizing radiation. They are mainly ultraviolet radiation. Not cause ionization electrons pass but higher orbital levels which causes the occurrence of point mutations.
Chemical mutagens
Numerous substances have
mutagenicity, most drugs like LSD, caffeine, nicotine, opium, morphine, quinine
and many sweeteners.
Biological mutagens
- Transposons. They are mobile segments of DNA that can change position, moving to another location within the same or another chromosome. They can cause mutations when they cause an activation or inactivation unwanted gene to be inserted into the structural genes or regulators.
- Virus. They can cause changes in the expression of some genes. It is believed that the mutagenic viruses may perform its action to take in its genome DNA fragments taken from a previously infected cell parasitized incorporated into the new cell.
Bibliography:
AURORA APARICIO MANRIQUE. (S/f). Mutations.
05/10/15, de biology 2 website: http://ies.rosachacel.colmenarviejo.educa.madrid.org/aurora.pdf
Jose s. ramil. (S/f). Mutations. 12/10/15, de ciencias
Sitio web: http://www.tirsoferrol.org/ciencias/pdf/a10_mutacion.pdf
Paola Cerruti Mainardi.
(2006). Orphanet Journal of Rare Diseases. BioMed Central, 33, 1-9.
Enrique Gómez Galán. (S /
F). Turner syndrome. 23.10.15, Spanish Association of Pediatrics Website: http://www.spao.es/documentos/biblioteca/entrada-biblioteca-fichero-60.pdf
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