| rats, wistar | A strain of albino rat developed at the wistar institute that has spread widely at other institutions. This has markedly diluted the original strain. (12 Dec 1998) |
|---|---|
| rats, zucker | Two populations of zucker rats have been cited in research--the "fatty" or obese and the lean. The "fatty" rat (rattus norvegicus) appeared as a spontaneous mutant. The obese condition appears to be due to a single recessive gene. (12 Dec 1998) |
| mole rats | Any of several burrowing rodents of the families muridae and bathyergidae, found in eastern europe, africa, and asia. They have short limbs, small eyes with permanently closed lids, and no tail. Three genera spalax (muridae), heterocephalus (bathyergidae) and cryptomys (bathyergidae) are used frequently as experimental animals in biomedical research. (12 Dec 1998) |
| active mutant | A mutant with overt phenotypic expression. (05 Mar 2000) |
| amber mutant | A mutant with a mutation resulting in a UAG codon. (05 Mar 2000) |
| auxotrophic mutant | Mutant with a nutritional requirement not present in the wild type organism. Synonym: defective organism, deficiency mutant. (05 Mar 2000) |
| gap mutant | <molecular biology> A fruit fly of the genus Drosophila which is missing a number of adjacent segments because the segments failed to develop. (09 Oct 1997) |
| virulent phage mutant | A mutant of a phage that is unable to establish lysogeny. (05 Mar 2000) |
| relaxed mutant | A mutant bacterium that continues to synthesise RNA in a medium that lackscertain nutrients or amino acids which that sort of bacterium normallyneeds present before it can make RNA. (09 Oct 1997) |
| ced mutant | <organism> Giant multinucleate fresh water amoeba (up to 5mm long) much used for studies on the mechanism of cell locomotion. (18 Nov 1997) |
| cell division cycle mutant | A yeast cell which has cell division cycle genes that have mutated to become sensitive to temperature, at certain temperatures (usually high ones), various parts of the normal yeast cell cycle become abnormal, and in some strains the yeast cell does not survive at all. (09 Oct 1997) |
| petite mutant | <molecular biology, organism> A class of yeast mutants, most studied in Saccharomyces cerevisiae. Mutants grow slowly and rely on anaerobic respiration: mitochondria, although present, have reduced cristae and are functionally defective (termed promitochondria). There are three types of petite mutant: (i) Segregational mutants that show Mendelian behaviour and result from mutations in mitochondrial genes located in the nucleus. (ii) Neutral petites, which are recessive genotypes and result from the complete absence of mitochondrial DNA. (iii) Suppressive petites, in which most of the mitchondrial DNA is lost (60-99%), though what remains is often amplified. (06 Oct 1997) |
| minute mutant | <genetics, molecular biology> A class of recessive lethal mutants of Drosophila The heterozygotes grow more slowly, are smaller and less fertile than the wild type flies. There are about 40 loci that produce minute mutants. (18 Nov 1997) |
| cold-sensitive mutant | A mutant that is defective at low temperature but functional at normal temperature. Compare: temperature-sensitive mutant. (05 Mar 2000) |
| conditional-lethal mutant | A viral mutant that can replicate under some (permissive) conditions but not under other (restrictive or nonpermissive) conditions, the parent (wild type) strain being able to replicate under both conditions. See: suppressor-sensitive mutant, temperature-sensitive mutant. Synonym: conditional-lethal mutant. (05 Mar 2000) |