epitope(EP-i-tope) A part of a molecule that an antibody will recognize and bind to.
epizooticA disease simultaneously affecting a large number of animals.
EPSP synthaseAbbreviation for enolpyruvyl-shikimate 3-phosphate synthase.
EPSPSAbbreviation for enolpyruvyl-shikimate 3-phosphate synthase.
equational divisionA chromosome division in which the two chromatids of each duplicated chromosome separate longitudinally, prior to being incorporated into two daughter…
Escherichia coliA commensal bacterium inhabiting the human colon that is widely used in biology, both as a simple model of cell biochemical function and as a host for…
essential amino acidAn amino acid required for normal metabolism, but which cannot be synthesized by an organism. It therefore has to be supplied via feed or food.
essential derivation of varieties(Abbreviation: EDV). Genotypes very similar to an originating cultivar, obtained, for example, by the selection of a mutant or a variant individual from…
Essential elementAny of a number of elements required by living organisms to ensure normal growth, development and maintenance.
essential nutrientAny substance required by living organisms to ensure normal growth, development and maintenance.
essential requirementIn plant cell tissue culture, comprises inorganic salts, including all of the elements necessary for plant metabolism; organic factors (amino acids…
established culture1. An aseptic viable explant (See: micropropagation ). 2. A suspension culture subjected to several passages with a constant cell number per unit time.
estimated breeding value(Abbreviation: EBV). Twice the expected progeny difference. The difference is doubled because breeding value is a reflection of all the genes of an…
EstrogenA type of hormone made by the body that helps develop and maintain female sex characteristics and the growth of long bones.
ethanolCommonly used to disinfect plant tissues, glassware utensils and working surfaces in tissue culture manipulations; to precipitate aqueous solutions of…
ethephonA synthetic compound commonly used as a source of ethylene, a gaseous plant growth regulator.
Ethidium bromideA fluorescent dye used to stain DNA and RNA. The dye fluoresces when exposed to UV light.
ethyleneA gaseous plant growth regulator acting on various aspects of vegetative growth, fruit ripening and abscission of plant parts. Synonym: ethene.
ethylenediamine tetraacetic acid(Abbreviation: EDTA). A chelating compound. Used to keep nutrients, such as iron, bound in a soluble form that leaves them still available to the plant…
etiolationAn abnormal increase in stem elongation, accompanied by poor (if any) leaf development.
euchromatinChromosomal material that is stained less intensely by certain dyes. Thought to be the chromosomal domains which are gene-rich, since the DNA in these…
EugenicsThe application of the principles of genetics to the 'improvement' of humankind. Wholly discredited as a scientific approach since the Nazi period.
EukaryoteAn organism whose cells possess a nucleus and other membrane-bound vesicles, including all members of the protist, fungi, plant and animal kingdoms; and…
euploidAn organism or cell having a chromosome number that is an exact multiple of the haploid number.
EvapotranspirationThe net water loss (in vapour form) per unit area of land, both directly from the land surface, and indirectly through transpiring leaves.
excision repair DNArepair processes that involve the removal of a damaged or incorrect segment of one strand of double-stranded DNA and its replacement by the synthesis of a…
excitation wavelengthThe specific wavelength of light required to stimulate a fluorescent molecule, such as a labelled probe, to emit light at the (lower) emission wavelength.
excrete(ek-SKREET) To get rid of waste material from the blood, tissues, or organs by a normal discharge (such as sweat, urine, or stool).
exit site(Abbreviation: E site). The ribosome binding site that contains the free tRNA prior to its release.
exogenousProduced outside of; originating from, or due to, external causes. Opposite: endogenous.
Exogenous DNADNA that has been derived from one organism, and is to be introduced into a cell a different species. Also referred to as foreign DNA or heterologous DNA.
ExonA DNA sequence that is ultimately translated into protein. See DNA.
exonuclease III(Abbreviation: exo III). An Escherichia coli enzyme that removes nucleotides from the 3' hydroxyl ends of double-stranded DNA.
exopolysaccharideA polysaccharide that is secreted by a micro-organism into the surrounding environment.
exotoxinA toxin released by a bacterium into the medium in which it grows.
expected progeny difference(Abbreviation: EPD). The predicted performance of the future offspring of an individual for a particular trait, calculated from measurement(s) of the…
explantA portion of a plant aseptically excised and prepared for culture in a nutrient medium.
explant donorThe plant from which an explant has been taken.
explantationThe removal of cells, tissues or organs of animals and plants for observation of their growth and development in appropriate culture media.
explosion methodA technique for the genetic transformation of cells, in which the transgene is driven into the target (plant) cells by the sudden vaporization (effected…
exportData extracted or taken out of one environment or application usually in a prescribed format, and usually for import into another environment or…
ExpressTo translate a gene's message into a molecular product.
expressed sequence tag(Abbreviation: EST). Partially sequenced cDNA clone. Because the read length of a standard DNA sequencing reaction is shorter than the majority of cDNA…
expression systemCombination of host and vector which provides a genetic context for making a cloned gene functional, i.e. produce peptide, in the host cell.
expression vectorA cloning vector that has been constructed in such a way that, after insertion of a DNA molecule, its coding sequence is properly transcribed and the mRNA…
expressivityDegree of expression of a trait controlled by a particular gene. The gene may show different degrees of expression in different individuals.
extensionThe short single-stranded stretch of nucleotides remaining on a double-stranded DNA molecule, following treatment with a restriction endonuclease which…
extrachromosomalIn eukaryotes, non-nuclear DNA, present in cytoplasm organelles such as mitochondria and chloroplasts . In prokaryotes, non-chromosomal DNA, i.e. plasmids.
extranuclear genesGenes residing elsewhere than in the nucleus (e.g. in mitochondria, chloroplasts or plastids).
exudeSlowly discharge liquid material (such as tannins or oxidized polyphenols from plant material) through pores or cuts, or by diffusion into the medium.