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A somatic mutation is a change in the DNA sequence of a somatic cell of a multicellular organism with dedicated reproductive cells; that is, ... for example, germ ...
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.
Somatic evolution is the accumulation of mutations and epimutations in somatic cells (the cells of a body, as opposed to germ plasm and stem cells) during a lifetime, and the effects of those mutations and epimutations on the fitness of those cells.
The frequency of mutations in mouse somatic tissue (brain, liver, Sertoli cells) was compared to the mutation frequency in male germline cells at sequential stages of spermatogenesis. [3] The spontaneous mutation frequency was found to be significantly higher (5 to 10-fold) in the somatic cell types than in the male germline cells. [3]
With plants, some somatic mutations can be propagated without the need for seed production, for example, by grafting and stem cuttings. These type of mutation have led to new types of fruits, such as the "Delicious" apple and the "Washington" navel orange. [93]
The COSMIC (Catalogue of Somatic Mutations in Cancer) database was designed to collect and display information on somatic mutations in cancer. It was launched in 2004, with data from just four genes, HRAS, KRAS2, NRAS and BRAF. [6] These four genes are known to be somatically mutated in cancer. Since its creation, the database has expanded rapidly.
The somatic mutations and epigenetic alterations caused by DNA damage and deficiencies in DNA repair accumulate in field defects. Field defects are normal-appearing tissues with multiple alterations (discussed in the section below), and are common precursors to development of the disordered and over-proliferating clone of tissue in a cancer.
Curt Stern in 1935 assumed that the structural changes in the chromosomes took place as a result of somatic crossing, as a result of which mutations or small chromosomal rearrangements in somatic cells. Thus the inert region causes an increase in mutation frequency or small chromosomal rearrangements in active segments adjacent to inert regions ...