Birgid Schlindwein's
Hypermedia Glossary Of Genetic Terms
Search Results
Birgid Schlindwein'sHypermedia Glossary Of Genetic TermsSearch Results |
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| Haplotype | A set of closely linked genetic markers present on one chromosome which tend to be inherited together (not easily separable by recombination). Some haplotypes may be in linkage disequilibrium. |
| Linkage | An association in inheritance between characters such that the parental character combinations appear among the progeny more often than the non-parental. The proximity of two or more markers (e.g. genes, RFLP markers) on a chromosome; the closer together the markers are, the lower the probability that they will be separated during DNA repair or replication processes (binary fission in prokaryotes, mitosis or meiosis in eukaryotes), and hence the greater the probability that they will be inherited together. Cf. recombination, complete linkage, partial linkage, non-linkage, linkage equilibrium, linkage disequilibrium. |
| Marker | An identifiable physical location on a chromosome (e.g., restriction enzyme cutting site, gene, minisatellite, microsatellite) whose inheritance can be monitored. Markers can be expressed regions of DNA (genes) or some segment of DNA with no known coding function but whose pattern of inheritance can be determined. See RFLP, restriction fragment length polymorphism. |
| Chromosome | The term was proposed by Waldeyer (1888) for the individual threads within a cell nucleus (gk. chroma, colour; soma, body). The self-replicating genetic structures of cells containing the cellular DNA that bears in its nucleotide sequence the linear array of genes. In prokaryotes, chromosomal DNA is circular, and the entire genome is carried on one chromosome. Eukaryotic genomes consist of a number of chromosomes whose DNA is associated with different kinds of proteins. |
| Inheritance | Trait which is derived by an heir from an ancestor; transmission and reception by animal or plant generation. Trait acquired via biological heredity that passes from parent to offspring. |
| Recombination | The process by which progeny derive a combination of linked genes different from that of either parent. In higher organisms, this can occur by crossing over between their loci during meiosis. Recombination may come about through random orientation of non-homologous chromosome pairs on the meiotic spindles, from crossing-over between homologous chromosomes, from gene conversion, or by other means. See homologous recombination. |
| Linkage disequilibrium | When the observed frequencies of haplotypes in a population does not agree with haplotype frequencies predicted by multiplying together the frequency of individual genetic markers in each haplotype. This results from a more or less recent mutation in one of two linked alleles. So some allele combinations occure more frequnetly than others. The disequilibrium decreases from generation to generation by crossing over and recombination. Cf. linkage equilibrium. |