| restriction length polymorphism | Fragment length polymorphism, the existence of allelic forms recognizable by the length of fragments that result when the nucleotide chain is treated by a specific restriction enzyme that cleaves wherever a particular sequence of nucleotides occurs. A mutation in this sequence changes cleaving and hence the number of fragments. (05 Mar 2000) |
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| restriction-site polymorphism | DNA polymorphism in which the sequence of one form of the polymorphism contains a recognition site for a particular endonuclease, but the sequence of the other form lacks such a site. (05 Mar 2000) |
| corneal endothelial polymorphism | A greater than normal variation in the shape of the cells. (05 Mar 2000) |
| polymorphism | 1. <genetics> The regular and simultaneous occurrence in a single interbreeding population of two or more alleles of a gene, where the frequency of the rarer alleles is greater than can be explained by recurrent mutation alone (typically greater than 1%). The concept includes chromosome polymorphism. HLA alleles of the major histocompatibility complex are very polymorphic. 2. <zoology> The differentiation of various parts of the units of colonial animals into different types of unit specialised for different purposes, for example as in the colonial hydroid Obelia. (04 Jul 1999) |
| DNA polymorphism | A condition in which one of two different but normal nucleotide sequences can exist at a particular site in DNA. (05 Mar 2000) |
| lipoprotein polymorphism | Heritable variations in low density beta-lipoproteins; the variant lipoproteins exhibit different antigenic and chemical properties when compared with normal lipoproteins. (05 Mar 2000) |
| single | 1. One only, as distinguished from more than one; consisting of one alone; individual; separate; as, a single star. "No single man is born with a right of controlling the opinions of all the rest." (Pope) 2. Alone; having no companion. "Who single hast maintained, Against revolted multitudes, the cause Of truth." (Milton) 3. Hence, unmarried; as, a single man or woman. "Grows, lives, and dies in single blessedness." (Shak) "Single chose to live, and shunned to wed." (Dryden) 4. Not doubled, twisted together, or combined with others; as, a single thread; a single strand of a rope. 5. Performed by one person, or one on each side; as, a single combat. "These shifts refuted, answer thy appellant, . . . Who now defles thee thrice ti single fight." (Milton) 6. Uncompounded; pure; unmixed. "Simple ideas are opposed to complex, and single to compound." (I. Watts) 7. Not deceitful or artful; honest; sincere. "I speak it with a single heart." (Shak) 8. Simple; not wise; weak; silly. "He utters such single matter in so infantly a voice." (Beau & Fl) Single ale, beer, or drink, small ale, etc, as contrasted with double ale, etc, which is stronger. Single bill, a single rope running through a fixed block. Origin: L. Singulus, a dim. From the root in simplex simple; cf. OE. & OF. Sengle, fr. L. Singulus. See Simple, and cf. Singular. 1. To select, as an individual person or thing, from among a number; to choose out from others; to separate. "Dogs who hereby can single out their master in the dark." (Bacon) "His blood! she faintly screamed her mind Still singling one from all mankind." (More) 2. To sequester; to withdraw; to retire. "An agent singling itself from consorts." (Hooker) 3. To take alone, or one by one. "Men . . . Commendable when they are singled." (Hooker) Origin: Singled; Singling. Source: Websters Dictionary (01 Mar 1998) |
| single ascertainment | Method of ascertainment of locating affected individuals by hospital or clinic admission or another way in which probability of encountering the same family twice approaches zero; thus, the probability that a family will be ascertained is proportional to the number of affected members. (05 Mar 2000) |
| single-blind method | A method in which either the observer(s) or the subject(s) is kept ignorant of the group to which the subjects are assigned. (12 Dec 1998) |
| single bond | A covalent bond resulting from the sharing of one pair of electrons; e.g., H3C-CH3 (ethane). (05 Mar 2000) |
| single cell protein | <protein> Protein produced by single cells in culture, especially Candida species, that could be of possible commercial importance in providing food sources from biotechnological processes. (10 Oct 1997) |
| single channel recording | Variant of patch clamp technique. (18 Nov 1997) |
| single-foot | An irregular gait of a horse; called also single-footed pace. See Single, "Single-foot is an irregular pace, rather rare, distinguished by the posterior extremities moving in the order of a fast walk, and the anterior extremities in that of a slow trot." (Stillman (The Horse in Motion)) Source: Websters Dictionary (01 Mar 1998) |
| single-gene diseases | Hereditary disorders caused by a change (mutation) in a single gene. There are thousands of single-gene diseases including achondroplastic dwarfism, huntington disease, cystic fibrosis, sickle cell disease, duchenne muscular dystrophy, and haemophilia. Single-gene diseases typically describe classic simple mendelian patterns of inheritance (as autosomal dominant, autosomal recessive, and x-linked traits) by comparison with polygenic diseases. (12 Dec 1998) |
| single gene disorder | Hereditary disorder caused by a mutant allele of a single gene (for example, Duchenne muscular dystrophy, retinoblastoma, sickle cell disease). Compare: polygenic disorders. (09 Oct 1997) |