| SSI | segmental sequential irradiation; shoulder subluxation inhibition; small-scale integration; Social S... |
|---|---|
| SSI | 4,6 Somatic Symptom Index [of DIS] |
| private mutation | A rare mutation found usually only in a single family or a small population. It is like a privately printed book. (12 Dec 1998) |
|---|---|
| hereditary mutation | A gene change that occurs in a germ cell (an egg or sperm) to become incorporated in every cell in the body. Hereditary mutations (also called germline mutations) play a role in cancer as, for example, the eye tumour retinoblastoma and wilms' tumour of the kidney. (12 Dec 1998) |
| homeotic mutation | <embryology, genetics> A mutation that causes an organism to develop a homologous body part or structure in place of the part or structure that should normally be there (for example, developing a hand in place of a foot). (09 Oct 1997) |
| silent mutation | Mutations that have no effect on phenotype because they do not affect the activity of the product of the gene, usually because of codon ambiguity. (18 Nov 1997) |
| site specific mutation | An alteration of the structure of a gene at a specific sequence, usually referring to experimentally produced changes in gene sequence. (05 Mar 2000) |
| spontaneous mutation | A mutation which occurs by itself without first being affected by a mutagen, for example during the process of DNA replication. Spontaneous mutations arise at a remarkably constant rate. The rate that spontaneous mutations arise has been used as an evolutionary clock to estimate how closely related two (or more) separate species are to each other. (09 Oct 1997) |
| natural mutation | A mutation which occurs by itself without first being affected by a mutagen, for example during the process of DNA replication. Spontaneous mutations arise at a remarkably constant rate. The rate that spontaneous mutations arise has been used as an evolutionary clock to estimate how closely related two (or more) separate species are to each other. (09 Oct 1997) |
| neutral mutation | A mutation that has no selective advantage or disadvantage. Considerable controversy surrounds the question of whether such mutations can exist. (18 Nov 1997) |
| new mutation | Redundant term for a heritable trait present in the offspring but in neither parent, i.e., not a pre-existing mutant form inherited. (05 Mar 2000) |
| substitution mutation | A mutation caused by a nucleotide base being replaced by a different one. (09 Oct 1997) |
| nonsense mutation | <molecular biology> A mutation that causes a polypeptide chain to be ended prematurely. (13 Nov 1997) |
| null mutation | Change in a gene that leads to nothing, for example to no enzyme or to a nonfunctioning enzyme. (12 Dec 1998) |
| suppressor mutation | <molecular biology> Mutation that alleviates the effect of a primary mutation at a different locus. May be through almost any mechanism that can give a primary mutation, but perhaps the most interesting class are the amber and ochre supressors, where the anticodon of the tRNA is altered so that it mis reads the termination codon and inserts an amino acid, preventing premature termination of the peptide chain. (18 Nov 1997) |
| deletion mutation | <molecular biology> A mutation in which one or more (sequential) nucleotides is lost by the genome. If the number lost is not divisible by 3 and is in a coding region, the result is a frameshift mutation. (18 Nov 1997) |
| down promoter mutation | <molecular biology> A mutation (a change in base pair sequence) in a promoter region, this results in lower gene expression (less transcription of the gene occurs). (09 Oct 1997) |