transferaseA class of enzymes that catalyses the transfer of a group of atoms from one molecule to another.
TransformantIn prokaryotes, a cell that has been ge- netically altered through the uptake of foreign DNA.
transformation(TRANZ-for-MAY-shun) In medicine, the change that a normal cell undergoes as it becomes malignant.
Transformation efficiencyThe number of bacterial cells that uptake and express plasmid DNA divided by the mass of plasmid used (in transformants/microgram). (See Transformation.)
transformation efficiency or frequencyThe fraction of a cell population that takes up and integrates the introduced transgene; expressed as the number of transformed cells recovered divided by…
Transforming oncogeneA gene that upon transfection converts a previously immortalized cell to the malignant phenotype. (See Oncogene.)
transgenesisThe introduction of a gene or genes into animal or plant cells, which leads to the transmission of the input gene (transgene ) to successive generations.
TransgenicAn organism in which a foreign DNA gene (a transgene) is incorporated into its genome early in de- velopment.
Transgenic animalGenetically enginnered animal or offspring of genetically engineered animals. The transgenic animal usually contains material from at lease one unrelated…
Transgenic plantGenetically engineered plant or offspring of genetically engineered plants. The transgenic plant usually contains material from at least one unrelated…
transgressive variationThe appearance, in a segregating generation, of individuals showing expression of a trait outside the extremes defined by the parent of the cross that was…
transient expressionShort-term activity of a transgene following its introduction into. Transient expression usually implies non-integration of the transgene into the.
transitionThese are where one type of bottom material or structure changes to another, for instance, a rock pile to solid rock, or sand to gravel.
transition stageThe period between juvenile and reproductive stages of growth.
Transition-state intermediateIn a chemical reaction, an unstable and high-energy configuration assumed by reactants on the way to making products.
TranslationThe process of converting the genetic infor- mation of an mRNA on ribosomes into a polypeptide.
transposon taggingA method of gene isolation that exploits the disruption of normal gene expression that is the result of an insertion of a transposon within, or close to…
transversionThe substitution in DNA or RNA of one purine by a pyrimidine or vice versa. See: transition, base substitution.
tri-hybridThe hybrid offspring of a cross between parents carrying contrasting alleles at three loci.
tribrid proteinA fusion protein that has three segments, each encoded by parts of different genes.
trichomeA short filament of cells, resulting in a hair-like structure.
trinucleotide repeatTandem repeats of three nucleotides that are present in many genes. Commonly trinucleotide repeats have undergone variable expansion in copy number…
tripartite matingA process in which conjugation is used to transfer a plasmid vector to a when the plasmid vector is not self-mobilizable.
tripletA sequential group of three nucleotides in DNA or RNA. See: codon.
triploidA cell, tissue or organism containing three times the haploid number of chromosomes.
trisomyThe presence in a diploid cell or organism of an extra chromosome of one homologue (chromosome formula: 2n + 1). See: disomy; monosomic.
triticaleThe hybrid man-made species formed by the crossing of tetraploid or hexaploid wheat with diploid rye.
tRNAAbbreviation for transfer RNA. Small RNA molecules that transfer amino acids to the ribosome during protein synthesis.
tRNA (transfer RNA)The class of small RNA molecules that transfer amino acids to the ribosome during protein synthesis. See Transfer RNA.
tropismPlant response to an external stimulus, resulting in the bending/turning of stem or root growth.
true-to-typeConforming to the phenotype of the breed/variety.
TrypsinA proteolytic enzyme that hydrolyzes peptide bonds on the carboxyl side of the amino acids arginine and lysine.
trypsin inhibitorSubstances inactivating trypsin, typically found in of certain plants, where they are thought to have evolved as anti-feedant agents against insect…
TSCAThe Toxic Substances Control Act. See Environmental Protection Agency.
TTPAbbreviation for thymidine 5'-triphosphate. TTP is required for DNA synthesis since it is a direct precursor molecule. See: thymidine, thymidylic acid.
tubulin(TOO-byuh-lin) One of a group of proteins found in high levels in the cell cytoplasm (fluid inside a cell but outside the cell's nucleus).
tumble tubeA glass tube mainly used in vitro to agitate and consequently aerate suspension cultures.
tunicaThe outer one- to four-cell layer region of the apical meristem, where cell division is anticlinal, i.e. perpendicular to the surface.
turbidostatAn open continuous culture in which a pre-selected biomass density is uniformly maintained by automatic removal of excess cells.
turgidSwollen, distended; referring to a cell that is extended as a result of adequate water uptake. Loss of turgidity in plant cells is a sign of water deficit.