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A major section of an organism therefore might carry the same mutation, especially if that mutation occurs at earlier stages of development. [2] Somatic mutations that occur later in an organism's life can be hard to detect, as they may affect only a single cell—for instance, a post-mitotic neuron; [3] [4] improvements in single cell ...
A related theory is that mutation, as distinct from DNA damage, is the primary cause of aging. A comparison of somatic mutation rate across several mammal species found that the total number of accumulated mutations at the end of lifespan was roughly equal across a broad range of lifespans. [49]
Mutation and DNA damage are the two major types of errors that occur in DNA, but they are fundamentally different. DNA damage is a physical alteration in the DNA structure, such as a single or double strand break, a modified guanosine residue in DNA such as 8-hydroxydeoxyguanosine, or a polycyclic aromatic hydrocarbon adduct. DNA damages can be ...
Bile acids cause DNA damage, including oxidative DNA damage, double-strand DNA breaks, aneuploidy and chromosome breakage. [55] High-normal levels of the bile acid deoxycholic acid cause apoptosis in human colon cells, [ 56 ] but may also lead to colon cancer if repair and apoptotic defenses are insufficient.
Human somatic variations are somatic mutations (mutations that occur in somatic cells) both at early stages of development and in adult cells. These variations can lead either to pathogenic phenotypes or not, even if their function in healthy conditions is not completely clear yet.
As well as mutations to DNA damage repair genes, mutations also arise in the genes responsible for arresting the cell cycle to allow sufficient time for DNA repair to occur, and some genes are involved in both DNA damage repair and cell cycle checkpoint control, for example ATM and checkpoint kinase 2 (CHEK2) – a tumor suppressor that is ...
This damage can then either be repaired perfectly, and no mutations will be present, or repaired imperfectly, resulting in a variety of mutations. [11] Exogenous mutagens include harmful chemicals and ionizing radiation ; the major difference between germline mutations and somatic mutations is that germ cells are not exposed to UV radiation ...
The somatic mutation theory of ageing states that accumulation of mutations in somatic cells is the primary cause of aging. A comparison of somatic mutation rate across several mammal species found that the total number of accumulated mutations at the end of lifespan was roughly equal across a broad range of lifespans. [16]