July 1, 2022
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, producing up to a million individual molecular damages per cell per day. Many of these damages cause structural disturbances in the DNA molecule, which can alter or eliminate the cell's ability to transcribe the gene that the damaged DNA segment encodes. Other damage induces potentially deleterious mutations of the cell genome, which affect the survival of daughter cells after mitosis. Consequently, the DNA repair process is constantly active. When the normal repair process fails, and cell apoptosis occurs, irreversible DNA damage occurs, including double-strand breaks and cross-links. The rate of DNA repair depends on many factors, including cell type, age, and the extracellular environment. A cell that has accumulated large amounts of DNA damage, or a cell that no longer has the ability to effectively repair the damage, can assume one of the following possible states: an irreversible state of rest, known as senescence cell suicide, also known as apoptosis or programmed cell death uncontrolled cell division, which can lead to the formation of tumors that are cancerous The ability of a cell to repair its DNA is vital for the integrity of its genome and therefore for its normal functioning. Many of the genes initially shown to affect lifespan are actually involved in DNA repair and protection. Failure to correct molecular lesions in the cells that make up the gametes can introduce mutations into the genomes of offspring and thus affect the rate of evolution.