DNA damage systematically causes mutations in the genome and changes genetic information.
The pathways of DNA damage are divided into
Exogenous: due to physical factors (such as UV rays and X and gamma ionizing rays) and chemical factors (desaminants, alkylating agents, oxidizing agents, adducts, nucleotide analogues ...).
Endogenous: they are physiological factors (oxidation desamination, depurination ...).
The consequences of these lesions are:
* Nucleotide substitution (one or more nucleotides)
* Insertion and deletion of nucleotides (one or more nucleotides): addition or deletion of nucleotides within the genome.