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Related to somatic mutation: Somatic hypermutation
1. a permanent transmissible change in the genetic material.
2. an individual exhibiting such a change.
point mutation a mutation resulting from a change in a single base pair in the DNA molecule.
somatic mutation a genetic mutation occurring in a somatic cell, providing the basis for mosaicism.
suppressor mutation the correction of the effect of a mutation at one locus by a mutation at another locus.
a mutation occurring in the general body cells (as opposed to the germ cells) and hence not transmitted to progeny.
Etymology: Gk, soma, body; L, mutare, to change
a sudden change in the chromosomal material in somatic cell nuclei affecting derived cells but not offspring.
Acquired MutationGenetics A post-meiotic alteration in a DNA sequence, which can be passed to the mutated cell’s progeny and linked to the development of cancer.
Molecular biology A non-heritable genetic change in a somatic cell; a somatic mutation.
so·mat·ic mu·ta·tion(sō-mat'ik myū-tā'shŭn)
A change that occurs in the general body cells (as opposed to the germ cells) and hence not transmitted to progeny.
somatic mutationA mutation affecting SOMATIC cells that can affect only those cells and their offspring, so cannot be passed on to future generations. Such a mutation dies with the death of the individual.
somatic mutationsee MUTATION.
1. a nucleotide change, including base substitutions, insertions or deletions in DNA, or RNA in the case of some viruses, that gives rise to the mutant phenotype.
2. an animal exhibiting such change. Called also a sport.
see reverse mutation (below).
base substitution mutation
may be a transition in which a purine-pyrimidine pair is substituted by the other purine-pyrimidine pair, or transversion in which a purine-pyrimidine pair is replaced by one of the two pyrimidine pairs.
chain termination mutation
one in which the new base sequence introduces a stop codon and thereby prematurely terminates synthesis of the polypeptide; the three mutations are also called amber (UAG), ochre (UAA) and opal (UGA).
one produced by loss of nucleotides from a DNA sequence.
frame shift mutation
occur as a result of either the insertion of a new base pair or the deletion of a base pair or a block of base pairs from the DNA base sequence; these, unless they occur in 3 or multiples of 3, are most serious in that the message to the right of the frame shift is garbled.
one in which the amino acid substitution only partially disrupts the function of the protein; in bacteria this is usually manifested by reduced growth rate.
one causing an amino acid substitution in the protein.
one in which a stop codon is substituted for a codon that specifies an amino acid.
operator constitutive mutation
one or more base changes in the operator region (originally defined for the lactose operon) which stop the repressor protein from tightly binding to sequence such that it is less effective in preventing RNA polymerase from inhibiting transcription.
a single changed base pair in the DNA of an organism which may be a base substitution, base insertion or base deletion.
the frequency of mutations in the population over time.
in regulation of gene expression, a mutation in the repressor protein that decreases the binding affinity of the repressor protein for the operator which leaves the gene permanently turned on.
one in which the wild-type phenotype is restored; such organisms are called revertants. Called also back mutation, reversion mutation.
see suppressor mutation.
one in which there is a base change but because of the redundancy of the genetic code the same amino acid is coded, or one in which there is an amino acid substitution in the protein which has no detectable effect on the phenotype.
a change in the DNA sequence that occurs in somatic cells, i.e. not gametes. The mechanism underlying the generation of diversity of antigen recognition by immunoglobulins and T cell receptor molecules. The fundamental cause of cancer, in which the mutation occurs spontaneously or is induced by carcinogens, such as sunlight, chemicals or viruses.
a particular type of reversion mutation in which a mutation at a second site restores the original phenotype; most simply a mutation produced by a base deletion may be restored to wild type by a proximate but independent base substitution. Called also second-site mutation.
temperature-sensitive (ts) mutation
one in which there is an altered protein that is active at one temperature, typically 86°F (30°C) and inactive at a higher temperature, usually 104 to 108°F (40 to 42°C), e.g. ts mutant virus and bacteria.
occur in genes producing diffusible products, in contrast to cis-dominant mutation in which mutations occur in regulatory sequences that are recognized by other proteins.
one in which the base change does not change the pyrimidine-purine orientation. See also base substitution mutation (above).
one produced by the insertion of a transposable genetic element.
one in which the purine-pyrimidine orientation is changed to pyrimidine-purine or vice versa. See also base substitution mutation (above).
1. pertaining to or characteristic of the body or soma.
2. pertaining to the body wall, not the viscera.
somatic afferent system
the system of sensory neurons scattered around the body and responding to pain, touch, temperature and other external stimuli.
see somatic cell.
somatic cell count (SCC)
measurement of somatic cells in milk. An indication of mastitis. See also linear score.
somatic cell hybridization
fusion in the laboratory of two different populations of somatic cells.
see somatic mutation.
somatic myoneural junction
see myoneural junction.
nerves supplying the body wall and limbs.
pain emanating from muscles, skeleton, skin; pain in the parts of the body other than the viscera.
central perceptions of sensory stimuli from the body wall and limbs include touch, temperature, tickle, itch, pain, conscious proprioception.
this postulates that very few immunoglobulins are inherited but there is great diversification in differentiating somatic cells.