| genetic diversity | <genetics> A property of a community of organisms of a certain species, in which members of the community have variations in their chromosomes due to a large number of slightly dissimilar ancestors, this property makes the community in general more resistant to diseases or to changing ecological conditions. (09 Oct 1997) |
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| genetic dominance | Denoting a pattern of inheritance of an autosomal mendelian trait due to a gene that always manifests itself phenotypically; generally, the phenotype in the homozygote is more severe than in the heterozygote, but details depend on what criterion of phenotyping is used. Dominance of traits, an expression of the apparent physiologic relationship existing between two or more genes that may occupy the same chromosomal locus (alleles). at a specific locus there are three possible combinations of two allelic genes, A and a: two homozygous (AA and aa) and one heterozygous (Aa). If a heterozygous individual presents only the hereditary characteristic determined by gene A, but not a, A is said to be dominant and a recessive; in this case, AA and Aa, although genotypically distinct, should be phenotypically indistinguishable. If AA, Aa, and aa are distinguishable, each from the others, A and a are codominant. (05 Mar 2000) |
| genetic drift | <genetics> The random change of the occurance of a particular gene in a population, genetic drift is thought to be one cause of speciation when a group oforganisms is separated from its parent population. (09 Oct 1997) |
| genetic engineering | <molecular biology, technique> General term covering the use of various experimental techniques to produce molecules of DNA containing new genes or novel combinations of genes, usually for insertion into a host cell for cloning. (07 May 1998) |
| genetic engineering technologies | See: recombinant DNAtechnologies. (09 Oct 1997) |
| genetic equilibrium | A condition in which the rate of an allele's forward mutation is cancelled out by its rate of reverse mutation. (09 Oct 1997) |
| genetic female | An individual with a normal female karyotype, including two X chromosomes, an individual whose cell nuclei contain Barr sex chromatin bodies, which are normally absent in males. (05 Mar 2000) |
| genetic fine structure | The study of genes on the level of their nucleotide sequences and what happens to their molecular structure at that level. (09 Oct 1997) |
| genetic fingerprint | 1. An impression of the inked bulb of the distal phalanx of a finger, showing the configuration of the surface ridges, used as a means of identification. See: dermatoglyphics, Galton's system of classification of fingerprints. 2. Term, sometimes used informally, referring to any analytical method capable of making fine distinctions between similar compounds or gel patterns; e.g., the pattern of an infrared absorption curve or of a two-dimensional paper chromatograph. 3. In genetics, the analysis of DNA fragments to determine the identity of an individual or the paternity of a child. Synonym: genetic fingerprint. (05 Mar 2000) |
| genetic fingerprinting | The process of comparing the nucleotide sequences of different DNA samples to find out if the samples are from the same individual or not. This is often used as a way to investigate crime, for example by comparing samples found at the crime scene with samples from the suspects. (09 Oct 1997) |
| genetic fitness | In a phenotype, the mean number of surviving offspring that it generates in its lifetime, usually expressed as a fraction or percentage of the average genetic fitness of the population. (05 Mar 2000) |
| genetic fixation | The increase of the frequency of a gene by genetic drift until no other allele is preserved in a specific finite population. (05 Mar 2000) |
| genetic heterogeneity | The presence of apparently similar characters for which the genetic evidence indicates that different genes or different genetic mechanisms are involved in different pedigrees. In clinical settings genetic heterogeneity refers to the presence of a variety of genetic defects which cause the same disease, often due to mutations at different loci on the same gene, a finding common to many human diseases including alzheimer's disease, cystic fibrosis, lipoprotein lipase and polycystic kidney disease. (12 Dec 1998) |
| genetic homeostasis | The tendency of a population to reach a point of genetic equilibrium and resist changes. Origin: Gr. Stasis = stoppage (09 Oct 1997) |
| genetic human male | An individual with a karyotype containing a Y chromosome, an individual whose cell nuclei do not contain Barr sex chromatin bodies, which are normally present in females. Patients with ambiguous sexual development and those with Turner's syndrome are classed as genetic male's or genetic females according to the absence or presence of Barr bodies even though their sex chromosome complement may suggest otherwise. (05 Mar 2000) |