| transversion mutation | A point mutation involving base substitution in which the orientation of purine and pyrimidine is reversed, in contradistinction to transition mutation. (05 Mar 2000) |
|---|---|
| umber mutation | A mutation yielding the termination codon UGA, resulting in premature termination of a polypeptide chain. Compare: suppressor mutation. Synonym: opal mutation. (05 Mar 2000) |
| unstable mutation | <molecular biology> A mutation that has a high likelihood of reverting to its original form. (13 Nov 1997) |
| up mutation | <molecular biology> Refers to any mutation in the promoter region of a gene which can trigger transcription initiation. (09 Oct 1997) |
| up promoter mutation | A mutation that increases the frequency of initiation of transcription. (05 Mar 2000) |
| forward mutation | Any mutation which renders a formerly functional gene nonfunctional. Compare: back mutation. (09 Oct 1997) |
| 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) |
| lethal mutation | <genetics, molecular biology> Mutation that eventually results in the death of an organism carrying the mutation. (18 Nov 1997) |
| bovine virus diarrhoea virus | A virus of the genus Pestivirus, in the family Togaviridae, causing bovine virus diarrhoea; New York, Oregon, and Indiana strains of the virus are recognised. Synonym: mucosal disease virus. (05 Mar 2000) |
| abelson leukaemia virus | A defective murine leukaemia virus capable of transforming lymphoid cells and producing a rapidly progressing lymphoid leukaemia after superinfection with friend, moloney, or rauscher virus. (12 Dec 1998) |
| Abelson murine leukaemia virus | A retrovirus belonging to the Type C retrovirus group subfamily (family Oncovirinae) which is associated with leukaemia and produces in vitro transformation of mouse cells. (05 Mar 2000) |
| adeno-associated virus | <virology> A genus of viruses in the family Parvoviridae which are all defective viruses (unable to replicate by themselves) and depend on the co-infection of their host cell by other, nondefective viruses to help them replicate. (09 Oct 1997) |
| adenoidal-pharyngeal-conjunctival virus | <virology> An icosahedral (20-sided) virus that contains DNA, there are over 40 different adenovirus varieties, some of which cause the common cold. (10 May 1997) |
| adenosatellite virus | <virology> A genus of viruses in the family Parvoviridae which are all defective viruses (unable to replicate by themselves) and depend on the co-infection of their host cell by other, nondefective viruses to help them replicate. (09 Oct 1997) |
| african horse sickness virus | A species of orbivirus that causes disease in horses, mules, and donkeys. (12 Dec 1998) |