mutation /mu·ta·tion/ (mu-ta´shun) a permanent transmissible change in the genetic material. Also, an individual exhibiting such change; a sport.
Mutation
mutation
mutation (mūtā´sh
n),
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 a mosaic condition.
suppressor mutation a mutation that partially or completely masks phenotypic expression of a mutation but occurs at a different site from it (i.e., causes suppression); it may be intragenic or intergenic. It is used particularly to describe a secondary mutation that suppresses a nonsense codon created by a primary mutation.
mu·ta·tion (my -t  sh n)n. 1. The act or process of being altered or changed. 2. An alteration or change, as in nature, form, or quality. 3. A sudden structural change within a gene or chromosome of an organism resulting in the creation of a new character or trait not found in the parental type. 4. The process by which such a sudden structural change occurs, either through an alteration in the nucleotide sequence of the DNA coding for a gene or through a change in the physical arrangement of a chromosome. 5. A mutant. mu·ta tion·al adj. |
Mutation
A permanent change in the genetic material that may alter a trait or characteristic of an individual, or manifest as disease, and can be transmitted to offspring.
Mentioned in: Achondroplasia, Ataxia-Telangiectasia, Colon Cancer, Familial Polyposis, Genetic Testing, Hemophilia, Lesch-Nyhan Syndrome, Monkeypox, Neurofibromatosis, Osteogenesis Imperfecta, Pervasive Developmental Disorders, Phenylketonuria, Prader-Willi Syndrome, Pseudoxanthoma Elasticum, Pyruvate Kinase Deficiency, Rectal Cancer, Sickle Cell Disease, Thalassemia, Von Willebrand Disease, Wiskott-Aldrich Syndrome, X-Linked Agammaglobulinemia
mutation
[myo̅o̅tā′shən]
Etymology: L, mutare, to change
an unusual change in a gene occurring spontaneously or by induction. The change affects the original expression of the gene. If a mutation occurs in the genome of a gamete, the mutation may be transmitted to later generations. mutate, v., mutational, adj.
mutation (mūtā´sh
n),n a departure from the parent type, as when an organism differs from its parents in one or more heritable characteristics; caused by genetic change.
mutation, gene,
n a sudden and permanent change in a gene. The term mutation is sometimes used in a broader sense to include chromosome aberrations.
mutation, lethal,
n a mutation leading to death of the offspring at any stage.
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.
back mutation
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).
deletion mutation
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.
leaky mutation
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.
mis-sense mutation
one causing an amino acid substitution in the protein.
nonsense mutation
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.
point mutation
a single changed base pair in the DNA of an organism which may be a base substitution, base insertion or base deletion.
mutation rate
the frequency of mutations in the population over time.
repressor-constitutive mutation
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.
reverse mutation
one in which the wild-type phenotype is restored; such organisms are called revertants. Called also back mutation, reversion mutation.
second-site mutation
see suppressor mutation.
silent 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.
somatic mutation
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.
suppressor mutation
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.
transdominant mutation
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.
transition mutation
one in which the base change does not change the pyrimidine-purine orientation. See also base substitution mutation (above).
transposition mutation
one produced by the insertion of a transposable genetic element.
transversion mutation
one in which the purine-pyrimidine orientation is changed to pyrimidine-purine or vice versa. See also base substitution mutation (above).
mutation
A permanent transmissible change in the nucleotide sequence of the DNA within a gene, or a change in the physical structure of a chromosome. It can occur by substitution (one base or nucleotide is replaced by another), transition (a purine (adenine or guanine) is replaced by another purine or one pyrimidine (cytosine or thymine) is replaced by another pyrimidine), transversion (a pyrimidine is replaced by a purine or vice versa), deletion or insertion of one or more bases. Mutations can also occur in a chromosome as a result of inversion (a segment of chromosome is inserted in reverse order), deletion (a loss of a piece of chromosome) or translocation (a piece of chromosome attaches to another). Mutations result in the formation of a protein with an abnormal amino acid or an absence of the protein and these may result in disease but some mutations may be beneficial. Mutations may be caused by copying errors in the genetic material during cell division, by exposure to ultraviolet or ionizing radiation (X-rays, gamma rays), carcinogens, viruses, or spontaneously. See chromosome; gene.
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|