Somatic Mutation

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Related to Acquired Mutation: somatic mutation, conditional mutant

somatic mutation

[sō¦mad·ik myü′tā·shən]
A genetic change limited to a somatic cell lineage; a major cause of cancer in humans.

Mutation, Somatic


a mutation that occurs in a somatic cell and provides the basis for a mosaic condition, that is, the formation of certain body parts, tissues, or cells having a unique set of chromosomes or genes.

All the types of somatic mutations that occur in sexual cells may occur in the cells of a developing organism. These mutations include (1) an increase in the chromosome set as a whole after normal chromosomal division without the subsequent division of the nucleus and cell, (2) trisomy and monosomy of various chromosomes as a result of the migration of two daughter chromosomes to a single pole (instead of different poles), and (3) the loss of a chromosome in one of the daughter cells during division as a result of its entrapment in the zone of the equatorial plate.

Inversions, deletions, and translocations of chromosomal fragments and mutations of individual genes occur with varying frequency in somatic cells. The earlier a somatic mutation occurs in an organism’s development, the greater the number of cells that will inherit the mutation, provided that the mutation does not destroy the carrier cell and that the rate of the carrier cell’s proliferation does not decrease. Gene somatic mutations are manifested relatively rarely, because in the overwhelming majority of cases the function of the mutant gene or of the separated chromosomal fragment is compensated for by the presence of a normal homologous gene or a normal area in the homologous matching chromosome of a mutant chromosome. The manifestation of certain somatic mutations is suppressed by the proximity of normal tissue.

Somatic mutations may not be manifested when the corresponding part of a chromosome of the given tissue is inactive. In the early 1960’s it was established that somatic mutations play an important role in the pathogenesis of the abnormal development of the sexual system, in the causation of spontaneous abortions and congenital deformities, and in carcinogenesis.

In plants, cells that carry somatic mutations may be propagated vegetatively or when the mutant area forms flowers.


Vakhtin, Iu. B. Genetika somaticheskikh kletok. Moscow, 1974.


References in periodicals archive ?
The degree of mitochondrial impairment depends on how the inherited mutations affect the generation of free radicals, which in turn accelerate the accumulation of acquired mutations.
Research suggests that the decline of mitochondrial respiratory-chain function due to the accumulation of acquired mutations in the mtDNA is a major cause of aging Free radical damage has been implicated in the accumulation of mutations with age, particularly in the brain, heart skeletal muscle, and kidneys.
In the setting of long-term imatinib therapy, secondary or acquired mutations occur in KIT exons 13, 14, and 17 and PDGFRA exon 18.
Cancer is driven by acquired mutations in genes, and we are at a point where it soon will be possible to actually know every mutation in the tumors of each of our patients," said Dr.
22) Various acquired mutations in exon 2, or less commonly exon 3, ultimately yield a mutant N-terminally truncated GATA1 protein (designated GATA1s) that has been detected exclusively in patients with DS.
Acquired mutations in GATA1 in the megakaryoblastic leukemia of Down syndrome.
They specifically found that bed bugs in New York City have acquired mutations in their nerve cells, which blunt the neurotoxic effect of the pyrethroid toxins used against them.
103,107-110) Less frequent causes of acquired resistance to EGFR TKIs include acquired mutations of phosphatidylinositol-3-kinase (PI3K), transformation to small cell lung cancer, epithelial to mesenchymal transition, and KRAS mutations.

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