Somatic Mutation


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Related to Somatic Mutation: Somatic hypermutation

somatic mutation

[sō¦mad·ik myü′tā·shən]
(genetics)
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.

REFERENCE

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

V. P. EFROIMSON

References in periodicals archive ?
Prior to the investigations in medulloblastoma patients, they sequenced the mitochondrial genomic sequence of tumor tissues from 19 pilocytic astrocytomic patients and matched blood samples and found somatic mutations in 16 (84%) cases (30), too.
Since many of the diseases encountered in clinical practice show more than one molecular abnormality, we could adapt NGS based assays to have simultaneous detection of multiple somatic mutations in tens or hundreds of target genes that are associated with specific diseases.
Interspecific differences in the occurrence of somatic mutations have been highlighted in reef corals (Schweinsberg et al., 2015), but identifying biological and/or environmental mechanisms influencing the degree of genetic mosaicism remains elusive.
Caution is advised that the uninvolved tissue may contain hematopoietic cells, such as lymphocytes carrying the somatic mutations. Testing of blood or bone marrow during complete remission from AML may also be used to detect germline variants, as residual leukemic cells are negligible in these samples.
In summary, our comprehensive genetic profiling of choriocarcinoma showed that multiple somatic mutations occur in PPC.
Subsequent somatic mutation analysis by next-generation sequencing using the Ion AmpliSeq 50-gene Cancer Hotspot Panel v2 (Thermo Fisher Scientific) (5) was completed 18 days after resection and confirmed the V600E BRAF mutation detected earlier by the Idylla system, with no other clinically actionable mutations detected.
Both somatic mutations and germline variants were searched in COSMIC (Catalog of Somatic Mutations in Cancer; http://cancer.
Somatic mutations in both G proteins and G-protein coupled receptors have recently been implicated in up to 20% of all human cancers [12].
made significant headway in identifying that somatic mutations in MLH1 and MSH2 are a frequent cause for inactivating DNA MMR function and subsequent MSI generation within Lynch-like syndrome cancers [64].
Graf, "Genotoxicity testing of antiparasitic nitrofurans in the drosophila wing somatic mutation and recombination test," Mutagenesis, vol.
However, HCC-associated somatic mutations vary extensively among individuals and even within a single tumour.
Racial diversity of endometrial cancers [10] and non-small-cell lung cancer [11] were investigated by comparing somatic mutations in common cancer genes.