six-base cutterType II restriction endonucleases whose recognition site and cleavage site consist of a characteristic sequence of six nucleotide pairs.
Skin biopsyProcess of removing tissue, in this case skin, from living patients for diagnostic examination, or the tissue specimen obtained by that process.
small nuclear ribonucleoprotein(Abbreviation: snRNP). A complex of small nuclear RNA and nuclear protein, heavily involved in the post-transcriptional processing of mRNA, especially the…
small nuclear RNA(Abbreviation: snRNA ). RNA transcripts of 100-300 bp that associate with proteins to form small nuclear ribonucleoprotein particles.
Small nuclear RNA (snRNA)Short RNA transcripts of 100-300 bp that associate with proteins to form small nuclear ribonucleoprotein particles (snRNPs), which participate in RNA…
SNPThe most common type of change in DNA (molecules inside cells that carry genetic information).
soil ameliorationThe improvement of poor soils. Includes the fungal and bacterial break down of plant organic matter, to form humus; the release of minerals - such as…
Somatic cell(soh-MA-tik ...) Any of the body cells except the reproductive (germ) cells.
somatic cell embryogenesisThe process of differentiation of somatic embryos either from explant cells (direct embryogenesis), or from callus generated from explants (indirect…
Somatic cell gene therapyThe repair or replacement of a defective gene within somatic tissue. (See Somatic cell.)
Somatic cell genetic mutationA change in the genetic structure that is neither inherited nor passed to offspring. Also called acquired mutations. See also: germ line genetic mutation
somatic cell hybrid panelA panel of cells created by cell fusion, typically involving a reference species (e.g. hamster) and the species of interest (e.g.
Somatic cell nuclear transferA technique in which the nucleus of a somatic cell (any cell of the body except sperm cells and egg cells) is injected, or transfered, into an egg, that…
Somatic Cell Nuclear Transfer (SCNT)A method of cloning: transfer of the nucleus from a donor somatic cell into an enucleated egg to produce a cloned embryo.
somatic cell variantA somatic cell with unique characters not present in the other cells, and which could be selected for by an appropriate screen.
Somatic cellsCells of body tissues other than the germline.
somatic embryoAn organized embryo -like structure. Although morphologically similar to a zygotic embryo it is initiated from somatic plant cells.
somatic hybridizationNaturally occurring or induced fusion of somatic protoplasts or cells of two genetically different parents. The difference may be as wide as interspecific.
somatic hypermutationThe high frequency of mutation that occurs in the gene segments encoding the variable regions of immunoglobulins during the differentiation of B…
somatic reductionHalving of the chromosomal number of somatic cells; a possible method of producing "haploids" from somatic cells and calli by artificial means.
Somatic stem cellsNon-embryonic stem cells that are not derived from gametes (egg or sperm cells).
somatotropin(SOH-muh-toh-TROH-pin) A protein made by the pituitary gland that helps control body growth and the use of glucose and fat in the body.
SomiteOne of the longitudinal series of segments into which the body of many animals (including vertebrates) is divided. (Merriam-Webster on line)
sonicationDisruption of cells or DNA molecules by high frequency sound waves.
SOS responseThe synthesis of a whole set of DNA repair, recombination and replication proteins in bacteria suffering severe DNA damage (e.g.
source DNAThe DNA from an organism that contains a target gene, and used as the starting material in a cloning experiment.
source organismA bacterium, plant or animal from which DNA is purified and used in a cloning experiment.
Southern blotA nitrocellulose or nylon membrane to which DNA fragments previously separated by gel electrophoresis, have been transferred by capillary action.
Southern hybridizationA procedure in which a cloned, labelled segment of DNA is hybridized to DNA restriction fragments on a Southern blot.
Southern hybridization (Southern blotting)A procedure in which DNA restriction fragments are transferred from an agarose gel to a nitrocellulose filter, where the denatured DNA is then hybridized…
spacer sequenceA DNA sequence separating neighbouring genes; spacer sequences are not usually transcribed.
SPARAbbreviation for single primer amplification reaction.
spargerA device that introduces, into a bioreactor, air in the form of fine bubbles.
spatial autocorrelation statisticsA set of statistical parameters aimed to depict the spatial (geographical) pattern of genetic diversity in a population.
speciationThe evolutionary differentiation of a pre-existing species into one or more distinct species.
SpeciesOrganisms in the same genus that have similar characteristics.
specific combining ability(Abbreviation: SCA). A component of genetic variance calculable where a number of genotypes are intercrossed in all possible combinations.
specificityWhen referring to a medical test, specificity refers to the percentage of people who test negative for a specific disease among a group of people who do…
Spectral karyotype (SKY)A visualization of all of an organism's chromosomes together, each labeled with a different color.
spent mediumAfter sub-culture, medium which is discarded because it has been depleted of nutrients, dehydrated, or accumulated toxic metabolic products.
sperm competitionCompetition between different spermatozoa to fertilize the of a single female.
sperm sexingThe separation of mammalian sperm into those bearing an X chromosome and those bearing a Y chromosome, in order to be able to produce, via artificial…
spermatidImmature spermatozoon. One of the four cells formed at the end of the second meiotic division in spermatogenesis.
spermatocyteThe premeiotic parental cell of the spermatids; the primary spermatocyte before the initiation of the first meiotic division; the secondary spermatocyte…
spermatogenesisThe series of cell divisions in the testis as a result of which the formation and the maturation of the male gametes (i.e. sperm) are achieved.
spermatogonium(pl.: spermatogonia) Primordial male germ cell. These can either divide by mitosis to produce daughter cells, or enter a growth phase and differentiate…
spermatozoon(Abbreviation: sperm). (pl.: spermatozoa) The mature, mobile gametic cell of male animals, produced in the testis.
spharoblastNodule of wood which can give rise to adventitious shoots with juvenile characteristics.
spheroplast(AlteRNA tive spelling: sphaeroplast). A microbial or plant cell from which most of the cell wall has been removed, usually by enzymatic treatment.
spike1. An inflorescence in which the main axis is elongated and the flowers are sessile. 2.
spikeletThe unit of inflorescence in grasses, made up of a small group of florets.
spindleAn intracellular fibrous structure, involved in the control of chromosome movement in mitosis and meiosis.
Splice siteLocation in the DNA sequence where RNA removes the noncoding areas to form a continuous gene transcript for translation into a protein.
spliceosomeA complex of small nuclear ribonucleoproteins and other proteins that assemble on an immature mRNA and catalyse the excision of an intron. See: splicing.
Splicing1. During the maturation of eukaryotic mRNA, the process that removes intron sequences and covalently joins exon sequences. Synonym: editing. 2.
splicing junctionThe DNA sequence immediately surrounding the boundary between an exon and an intron.
split geneIn eukaryotes, the encoding DNA of many structural genes is made up of exons and introns .
Sporadic cancerCancer that occurs randomly and is not inherited from parents. Caused by DNA changes in one cell that grows and divides, spreading throughout the body.
sporangium(pl.: sporangia) A reproductive structure in plants that produces spores. A megasporangium produces megaspores, which give rise to the female gametophyte…
SporeA term used to describe a particle in plants, bacteria and fungi.
sporophyteThe diploid generation in the life cycle of a plant, and that produces haploid spores by meiosis.
sportAn individual plant, or portion thereof, showing a recognizably different phenotype from the parent, presumably as a result of spontaneous mutation.
SSRAbbreviation for simple sequence repeat. See: microsatellite.
stacked genesRefers to the insertion of two or more genes into the genome of an organism. An example would be a plant carrying a giving insect resistance, and a bar…
staggered cutsSymmetrically cleaved phosphodiester bonds that lie on both strands of double-stranded DNA, but are not opposite one another.
stamenFloral structure made up of an anther and a filament. The stamen is the male organ of a flower.
Standard deviationStandard deviation is a statistical measurement of how far a variable quantity, such as the price of a stock, moves above or below its average value.
standard errorThe standard error of an estimate is a measure of the sampling variability of the estimate.
starchA substance found in plants. It contains sugar molecules joined chemically. It is found in high levels in foods such as potatoes, rice, corn, and wheat.
StarLinkTMAn insect-resistant variety of corn that was approved for animal feed only, not labeled for human consumption.
start codonThe codon which specifies the first amino acid of a polypeptide chain and at which the ribosome starts the process of translation.
Stationary phaseThe plateau of the growth curve after log growth, during which cell number remains constant. New cells are produced at the same rate as older cells die.
steady stateIn a continuous fermentation process, the condition under which the number of cells removed with the outflow is exactly balanced by the number of newly…