| recombination, genetic | Production of new arrangements of genes by various mechanisms such as assortment and segregation, crossing over, gene conversion, transformation, conjugation, transduction, f-duction, or mixed infection of viruses. (12 Dec 1998) |
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| mobile genetic element | <molecular biology> Small, mobile DNA sequences that can replicate and insert copies at random sites within chromosomes. They have nearly identical sequences at each end, oppositely oriented (inverted) repeats and code for the enzyme, transposase, that catalyses their insertion. Bacteria have two types of transposon, simple transposons that have only the genes needed for insertion and complex transposons that contain genes in addition to those needed for insertion. Eukaryotes contain two classes of mobile genetic elements, the first are like bacterial transposons in that DNA sequences move directly. The second class (retrotransposons) move by producing RNA that is transcribed, by reverse transcriptase, into DNA which is then inserted at a new site. (13 Nov 1997) |
| models, genetic | Theoretical representations that simulate the behaviour or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment. (12 Dec 1998) |
| conjugation, genetic | A parasexual mechanism in bacteria for achieving unidirectional transfer of all or part of the chromosome from an f+ or hfr donor ("male") to an f- ("female") recipient. (12 Dec 1998) |
| polymorphic genetic markers | Inherited characteristics that occur within a given population as two or more traits. (05 Mar 2000) |
| suppression, genetic | The restoration of the wild-type phenotype in an organism possessing a mutationally altered genotype. The effects of the mutation may be suppressed by a second "suppressor" mutation on a different gene, by a suppressor mutation on the same gene but located at a distance from the site of the primary mutation, or by the presence of a cytoplasmic suppressor due to a change in non-chromosomal DNA. (12 Dec 1998) |
| transcription, genetic | The transfer of genetic information from DNA to messenger RNA by DNA-directed RNA polymerase. It includes reverse transcription and transcription of early and late genes expressed early in an organism's life cycle or during later development. (12 Dec 1998) |
| transduction, genetic | Transfer of bacterial DNA by phages from the infected bacterium in which the DNA originates to another bacterium. (12 Dec 1998) |
| transformation, genetic | The unidirectional transfer and incorporation of foreign DNA by prokaryotic or eukaryotic cells and the subsequent recombination of part or all of that DNA into the cell's genome. (glossary of genetics: classical and molecular, 5th ed) (12 Dec 1998) |
| translation, genetic | Formation of peptides on ribosomes, directed by messenger RNA. (12 Dec 1998) |
| epistasis, genetic | A form of gene interaction whereby one gene interferes with the phenotypic expression of another nonallelic gene or genes. Genes whose expression is altered by nonallelic genes are said to be "hypostatic" or to exhibit "hypostasis". (12 Dec 1998) |
| acoustic nerve diseases | Diseases of the eighth cranial nerve. These include vestibular neuronitis, cochlear neuritis and acoustic neuroma. (12 Dec 1998) |
| adaptation diseases | Disease's falling theoretically into Selye's concept of the general-adaptation syndrome. (05 Mar 2000) |
| adnexal diseases | Diseases of the uterine appendages: the ovaries, uterine tubes, and ligaments of the uterus. (12 Dec 1998) |
| agricultural workers' diseases | Diseases in persons engaged in cultivating and tilling soil, growing plants, harvesting crops, raising livestock, or otherwise engaged in husbandry and farming. The diseases are not restricted to farmers in the sense of those who perform conventional farm chores: the heading applies also to those engaged in the individual activities named above, as in those only gathering harvest or in those only dusting crops. (12 Dec 1998) |