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The CSC model posits that the heterogeneity observed between tumour cells is the result of differences in the stem cells from which they originated. Stem cell variability is often caused by epigenetic changes, but can also result from clonal evolution of the CSC population where advantageous genetic mutations can accumulate in CSCs and their ...
Genetic markers have also been used to measure the genomic response to selection in livestock. Natural and artificial selection leads to a change in the genetic makeup of the cell. The presence of different alleles due to a distorted segregation at the genetic markers is indicative of the difference between selected and non-selected livestock. [5]
The disparity in mutation rate between the germline and somatic tissues likely reflects the greater importance of genetic integrity in the germline than in the soma. [12] Variation in mutation frequency may be due to differences in rates of DNA damage or to differences in the DNA repair process as a result of elevated levels of DNA repair enzymes.
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic , and epigenetic levels and abnormal cell division .
The term "variant' is favored in clinical practice over "mutation" because it can be used to describe an allele more precisely (i.e. without inherently connoting pathogenicity). When the variant has no impact on health, it is called a "benign variant". When it is associated with a disease, it is called a "pathogenic variant".
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.
In this way, a population of mutant cells, called a clone, can expand in the neoplasm. Clonal expansion is the signature of natural selection in cancer. Cancer therapies act as a form of artificial selection, killing sensitive cancer cells, but leaving behind resistant cells. Often the tumor will regrow from those resistant cells, the patient ...
A graphical representation of the typical human karyotype The human mitochondrial DNA. Human genetic variation is the genetic differences in and among populations.There may be multiple variants of any given gene in the human population (), a situation called polymorphism.