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Unlike in the case of normal cells, state switching in cancer cells is widely believed to arise due to somatic mutations. [4] However, there is growing concern that such a deterministic view of a phenomenon that is reversible is not entirely consistent with multiple lines of evidence which indicate that stochasticity may also play an important ...
[23] [24] Many bodily processes can be affected due to the hereditary nature of this disease; if the disease is present in the DNA of both the sperm and the egg, then it will be present in essentially every cell and organ in the body; these mutations can occur initially in the germline cells, or be present in all parental cells. [23]
Genome instability does occur in bacteria. [1] In multicellular organisms genome instability is central to carcinogenesis, [2] and in humans it is also a factor in some neurodegenerative diseases such as amyotrophic lateral sclerosis or the neuromuscular disease myotonic dystrophy.
Polyploidy is the result of whole-genome duplication during the evolution of species. It may occur due to abnormal cell division, either during mitosis, or more commonly from the failure of chromosomes to separate during meiosis or from the fertilization of an egg by more than one sperm. [1]
In medicine, study of human genetic variation may be important because some disease-causing alleles occur more often in certain population groups. For instance, the mutation for sickle-cell anemia is more often found in people with ancestry from certain sub-Saharan African, south European, Arabian, and Indian populations, due to the ...
Such mutations are responsible for diseases such as Epidermolysis bullosa, sickle-cell disease, and SOD1-mediated ALS. [52] On the other hand, if a missense mutation occurs in an amino acid codon that results in the use of a different, but chemically similar, amino acid, then sometimes little or no change is rendered in the protein.
For example, in mammals, somatic cells make up the internal organs, skin, bones, blood, and connective tissue. [1] In most animals, separation of germ cells from somatic cells (germline development) occurs during early stages of development. Once this segregation has occurred in the embryo, any mutation outside of the germline cells can not be ...
Cells in pre-malignant and malignant neoplasms evolve by natural selection. [1] [2] This accounts for how cancer develops from normal tissue and why it has been difficult to cure. There are three necessary and sufficient conditions for natural selection, all of which are met in a neoplasm: There must be variation in the population.