| ochre mutation | Mutation that changes any codon to the termination codon UAA. (18 Nov 1997) |
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| ochre | <chemical> A impure earthy ore of iron or a ferruginous clay, usually red (hematite) or yellow (limonite), used as a pigment in making paints, etc. The name is also applied to clays of other colours. A metallic oxide occurring in earthy form; as, tungstic ocher or tungstite. Origin: F.ocre, L. Ochra, fr. Gr, from pale, pale yellow. <chemical> See Ocher. Source: Websters Dictionary (01 Mar 1998) |
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| ochre codon | The codon UAA, one of the three that causes termination of protein synthesis. The most frequent termination codon in E. Coli genes. (18 Nov 1997) |
| ochre suppressor | A gene that codes for an altered tRNA so that its anticodon can recognise the ochre codon and thus allows the continuation of protein synthesis. A suppressor of an ochre mutation is a tRNA that is charged with the amino acid corresponding to the original codon or a neutral substitute. Ochre suppressors will also suppress amber codons. (18 Nov 1997) |
| uran-ochre | <chemical> A yellow, earthy incrustation, consisting essentially of the oxide of uranium, but more or less impure. Origin: Cf. F. Uranochre. Source: Websters Dictionary (01 Mar 1998) |
| acquired mutation | A change in a gene or chromosome that occurs in a single cell after the conception of the individual. That change is then passed along to all cells descended from that cell. Acquired mutations are involved in the development of cancer. (12 Dec 1998) |
| addition-deletion mutation | <molecular biology> A type of mutation that results from insertion or deletion of a single nucleotide into, or from, an open reading frame in the normal DNA sequence. Normally, the genetic code is read in the wrong frame, three nucleotides at a time, and the entire sequence downstream of the mutation, is translated into a polypeptide with a garbled amino acid sequence from the mutated codon onwards. These mutations may be induced by certain types of mutagens or may occur spontaneously and usually result in the generation, downstream, of nonsense, chain termination codons. Synonym: addition mutation, addition-deletion mutation, deletion mutation, reading-frameshift mutation. (21 Jun 2000) |
| addition mutation | <molecular biology> A type of mutation that results from insertion or deletion of a single nucleotide into, or from, an open reading frame in the normal DNA sequence. Normally, the genetic code is read in the wrong frame, three nucleotides at a time, and the entire sequence downstream of the mutation, is translated into a polypeptide with a garbled amino acid sequence from the mutated codon onwards. These mutations may be induced by certain types of mutagens or may occur spontaneously and usually result in the generation, downstream, of nonsense, chain termination codons. Synonym: addition mutation, addition-deletion mutation, deletion mutation, reading-frameshift mutation. (21 Jun 2000) |
| amber mutation | <molecular biology> A mutation from a codon which codes for an amino acid into the amber codon UAG, which normally signals that the translation of mRNA into an amino acid chain should stop. The mutation causes the amino acid chain to stop forming before it is actually completed. (09 Oct 1997) |
| back mutation | <molecular biology> A mutation that causes a mutant gene to revert to its original wild-type base sequence. Compare: forward mutation. (09 Oct 1997) |
| reading-frameshift mutation | <molecular biology> A type of mutation that results from insertion or deletion of a single nucleotide into, or from, an open reading frame in the normal DNA sequence. Normally, the genetic code is read in the wrong frame, three nucleotides at a time, and the entire sequence downstream of the mutation, is translated into a polypeptide with a garbled amino acid sequence from the mutated codon onwards. These mutations may be induced by certain types of mutagens or may occur spontaneously and usually result in the generation, downstream, of nonsense, chain termination codons. Synonym: addition mutation, addition-deletion mutation, deletion mutation, reading-frameshift mutation. (21 Jun 2000) |
| germinal mutation | A mutation in the germ cells (the cells which will undergo meiosis to form the gametes). Such mutations are therefore passed on to offspring. (09 Oct 1997) |
| germ-line mutation | Any detectable and heritable alteration in the lineage of germ cells. Mutations in these cells (i.e., "generative" cells ancestral to the gametes) are transmitted to progeny while those in somatic cells are not. (12 Dec 1998) |
| reverse mutation | <molecular biology> A mutation that causes a mutant gene to revert to its original wild-type base sequence. Compare: forward mutation. (09 Oct 1997) |
| chromosomal mutation | Can refer to any of a number of DNA mutations which results in a change in the protein encoded by the mutated gene, such as point mutations, insertion or deletion mutations (frameshift mutations), or nonsense mutations. More often this refers to mutations involving chromosomes, such as the inversion of part of one chromosome such that the inverted part no longer matches with its homologous pair, a translocation of one part of a chromosome to a different chromosome, deletions of parts of chromosomes, or accidents which happen during the division of the nucleus like the unequal portioning of chromosomes between the daughter cells. (09 Oct 1997) |
| missense mutation | <molecular biology> A mutation that alters a codon for a particular amino acid to one specifying a different amino acid. (18 Nov 1997) |