| RFLP | restriction fragment length polymorphism |
|---|---|
| Bmod | behavior modification |
| CM | California mastitis [test]; calmodulin; capreomycin; carboxymethyl; cardiac murmur; cardiac muscle; ... |
| CMS | children's medical services; Christian Medical Society; chronic myelodysplastic syndrome; chromosome... |
| EBM | electrophysiologic behavior modification; epidermal basement membrane; evidence-based medicine; expr... |
D factor
| restriction fragment | <molecular biology> The fragments of DNA generated by digesting DNA with a specific restriction endonuclease. Each of the fragments ends in a site recognised by that specific enzyme. (10 Mar 1998) |
|---|---|
| restriction fragment length polymorphism | <molecular biology, technique> A method that allows familial relationships to be established by comparing the characteristic polymorphic patterns that are obtained when certain regions of genomic DNA are amplified (typically by PCR) and cut with certain restriction enzymes. The variation in the length of DNA fragments produced by a restriction endonuclease that cuts at a polymorphic locus. Such variations are generated by mutations that create or abolish recognition sites for these enzymes. This is a key tool in DNA fingerprinting, reflecting the existence of different alleles in the individual. Restriction fragment length polymorphism mapping is also used in plant breeding to see if a key trait such as disease resistance is inherited. In principle, an individual can be identified unambiquously by restriction fragment length polymorphism hence the use of restriction fragment length polymorphism in forensic analysis of blood, hair or semen). Similarly, if a polymorphism can be identified close to the locus of a genetic defect, it provides a valuable marker for tracing the inheritance of the defect. Synonym: DNA fingerprinting. Acronym: RFLP (12 Jan 1998) |
| 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) |
| restriction map | <molecular biology> Map of DNA showing the position of sites recognised and cut by various restriction endonucleases. (12 Jan 1998) |
| restriction mapping | Use of restriction endonucleases to analyze and generate a physical map of genomes or genes. The nucleotide sequence determined is often then translated into an amino acid sequence, providing a means for sequencing the protein for which the gene codes, or for which the mRNA is a messenger. (12 Dec 1998) |
| restriction methylation | The enzymatic addition of methyl groups to selected adenine and cytosine residues to protect from hydrolysis by certain restriction enzymes. (05 Mar 2000) |
| restriction nuclease | <enzyme, molecular biology> Class of bacterial enzymes that cut DNA at specific sites. In bacteria their function is to destroy foreign DNA, such as that of bacteriophages (host DNA is specifically modified at these sites). Type I restriction endonucleases occur as a complex with the methylase and a polypeptide that binds to the recognition site on DNA. They are often not very specific and cut at a remote site. Type II restriction endonucleases are the classic experimental tools. They have very specific recognition and cutting sites. The recognition sites are short, 4-8 nucleotides and are usually palindromic sequences. Because both strands have the same sequence running in opposite directions the enzymes make double stranded breaks, which, if the site of cleavage is off centre, generates fragments with short single stranded tails, these can hybridise to the tails of other fragments and are called sticky ends. They are generally named according to the bacterium from which they were isolated (first letter of genus name and the first two letters of the specific name). The bacterial strain is identified next and multiple enzymes are given Roman numerals. For example the two enzymes isolated from the R strain of E. Coli are designated Eco RI and Eco RII. (10 Mar 1998) |
| restriction site | A sequence in DNA that can be recognised and cut by a specific restriction enzyme. (12 Dec 1998) |
| 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) |
| MHC restriction | <immunology> Restriction on interaction between cells of the immune system because of the requirement to recognise foreign antigen is association with MHC antigens (major histocompatibility antigens). Thus, cytotoxic T-cells will only kill virally infected cells that have the same Class I antigens as themselves, whereas helper T-cells respond to foreign antigen associated with Class II antigens. (18 Nov 1997) |
| DNA restriction enzymes | <enzyme> Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of dnas, and have made it possible to splice and recombine genes from one organism into the genome of another. Registry number: EC 3.1.21 (12 Dec 1998) |
| ecori restriction enzyme | <enzyme, molecular biology> A commonly-used restriction enzyme (enzyme which will cleave the phosphodiester bonds of DNA at specific nucleotide sequences) that came from the bacteria Escherichia coli and recognises the sequence GAATTC. The enzyme will make a staggered cut of the double-stranded DNA molecule by cutting between the G and A on both strands. (09 Oct 1997) |
| lactase restriction | An inherited trait in which there is low lactase activity and thus there is defective lactose intestinal metabolism. Compare: lactase persistence. (05 Mar 2000) |
| abstracting and indexing | Shortening or summarizing of documents; assigning of descriptors for referencing documents. (12 Dec 1998) |
| academies and institutes | Organizations representing specialised fields which are accepted as authoritative; may be non-governmental, university or an independent research organization, e.g., national academy of sciences, brookings institution, etc. (12 Dec 1998) |