GastrulaAn early animal embryo consisting of two layers of cells; an embryological stage following the blastula.
GastrulationThe process whereby the cells of the blastocyst are translocated to establish three germ layers.
GC islandA segment of double-stranded DNA that is rich in GC base pairs. This type of sequence is characteristic of eukaryotic genomic regions with a high gene…
GC-rich areaMany DNA sequences carry long stretches of repeated G and C which often indicate a gene-rich region.
gel filtrationA method of protein or DNA purification, where differences in size are used to separate the components of a complex mixture.
gelatinA glutinous, protein aceous gelling and solidifying agent. Gelatin is produced by the partial hydrolysis (via boiling) of collagen, found in the…
gelatinizationThe swelling of starch when added to hot water. Hydrolysis causes the molecule to lose structure, and technically gelatinization is not complete until…
GelriteTMThe brand name of a Pseudomonas-derived refined polysaccharide used as a gelling agent and agar substitute.
GeneThe functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a…
gene (resources) conservationThe conservation of species, populations, individuals or parts of individuals, by in situ or ex situ methods, to provide a diversity of genetic materials…
gene additionThe addition of a functional copy of a gene to the genome of an organism.
Gene amplificationThe presence of multiple genes. Amplification is one mechanism through which proto-oncogenes are activated in malignant cells.
gene bank1. The physical location where collections of genetic material in the form of seeds, tissues or reproductive cells of plants or animals are stored. 2.
Gene chip technologyDevelopment of cDNA microarrays from a large number of genes. Used to monitor and measure changes in gene expression for each gene represented on the chip.
Gene cloningThe process of synthesizing multiple copies of a particular DNA sequence using a bacteria cell or another organism as a host. See DNA, Host.
gene conversionA process, often associated with recombination, during which one allele is replicated at the expense of another, leading to non-Mendelian segregation…
gene expression(JEEN ek-SPREH-shun) The process by which a gene gets turned on in a cell to make RNA and proteins.
Gene familyGroup of closely related genes that make similar products.
Gene flowThe exchange of genes between different but (usually) related populations.
Gene frequencyThe percentage of a given allele in a population of organisms. See Allele.
gene regulationThe process of controlling the synthesis or suppression of gene products in specific cells or tissues.
gene replacementThe incorporation of a transgene into a chromosome at its normal location by homologous recombination, thus replacing the copy of the gene originally…
gene therapy(jeen THAYR-uh-pee) Treatment that alters a gene. In studies of gene therapy for cancer, researchers are trying to improve the body's natural ability to…
gene trackingFollowing the inheritance of a particular gene from generation to generation.
gene transferThe insertion of genetic material into a cell.
Gene translocationThe movement of a gene fragment from one chromosomal location to another, which often alters or abolishes expression.
generally regarded as safe(Abbreviation: GRAS). Designation given to foods, drugs, and other materials with a long-term history of not causing illness to humans, even though formal…
generative nucleusIn many flowering plants, shed pollen is two-celled (in others it is three-celled or has a variable number).
genetThe individual(s) descended vegetatively from a single sexually produced zygote, including all entities derived from it.
Genetic assimilationEventual extinction of a natural species as massive pollen flow occurs from another related species and the older crop becomes more like the new crop.
Genetic codeThe three-letter code that translates nucleic acid sequence into protein sequence.
genetic code (ATGC)The instructions in a gene that tell the cell how to make a specific protein. A, T, G, and C are the "letters" of the DNA code; they stand for the…
genetic complementationWhen two DNA molecules that are in the same cell together produce a function that neither DNA molecule can supply on its own.
genetic counseling(jeh-NEH-tik KOWN-suh-ling) A communication process between a specially trained health professional and a person concerned about the genetic risk of…
Genetic discriminationPrejudice against those who have or are likely to develop an inherited disorder.
Genetic diseaseA disease that has its origin in changes to the genetic material, DNA. Usually refers to diseases that are inherited in a Mendelian fashion, although…
genetic distanceA measure of the genetic similarity between any pair of populations. This is measured on the basis of variation in a combination of phenotypic traits…
genetic distancingThe collection of the data on phenotypic traits, marker allele frequencies or DNA sequences for two or more populations, and estimation of the genetic…
Genetic diversityThe variety of different types of genes in a species or population.
Genetic driftRandom variation in gene frequency from one generation to another.
Genetic engineeringThe manipulation of an organism's genetic endowment by introducing or eliminating specific genes through modern molecular biology techniques.
genetic equilibriumThe maintenance of a steady state with respect to allele frequencies in a group of interbreeding organisms.
genetic erosionThe loss over time of allelic diversity, particularly in farmed organisms, caused by either natural or man-made processes. See: genetic drift.
genetic gainThe increase in productivity achieved following a change in gene frequency effected by selection.
genetic heterogeneityOccurs where the genetic determination of a given phenotype differs between individuals.
Genetic illnessSickness, physical disability, or other disorder resulting from the inheritance of one or more deleterious alleles.
genetic immunizationDelivery to a host organism of a cloned gene that encodes an antigen. After the cloned gene is expressed, it elicits an antibody response that protects…
Genetic linkage mapA linear map of the relative positions of genes along a chromosome. Distances are established by linkage analysis, which determines the frequency at which…
genetic mapThe linear array of genes on a chromosome, based on recombination frequencies (linkage map) or physical location (physical or chromosomal map).
Genetic mosaicAn organism in which different cells contain different genetic sequence. This can be the result of a mutation during development or fusion of embryos at…
genetic pollutionUncontrolled spread of genetic information (frequently referring to transgenes ) into the genomes of organisms in which such genes are not present in…
Genetic predispositionAn inherited increase in the risk of developing a disease. Also called genetic susceptibility.
genetic relatednessA quantitative estimate of the proportion of genes, ®, shared between the genomes of any two individuals, groups or populations, e.g. r = 0.
Genetic screeningTesting a population group to identify a subset of individuals at high risk for having or transmitting a specific genetic disorder. See also
genetic selectionThe process of selecting genes, cells, clones, etc., within populations or between populations or species.
Genetic testingAnalyzing DNA to look for a genetic alteration that may indicate an increased risk for developing a specific disease or disorder.
genetic use restriction technology(Abbreviation: GURT). A proposed technology applying transgenesis to genetically compromise the fertility or the performance of saved seed of a cultivar…
genetic variationDifferences between individuals attributable to differences in genotype.