Gene Cloning and DNA Analysis: An Introduction, Sixth Edition ...

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Glossary
Single nucleotide polymorphism (SNP) A point mutation that is carried by some individuals
of a population.
Sonication A procedure that uses ultrasound to cause random breaks in DNA molecules.
Southern transfer A technique for transferring bands of DNA from an agarose gel to a
nitrocellulose or nylon membrane.
Sphaeroplast A cell with a partially degraded cell wall.
Spin column A method for accelerating ion-exchange chromatography by centrifuging
the chromatography column.
Stem–loop A hairpin structure, consisting of a base-paired stem and a non-base-paired
loop, that may form in a polynucleotide.
Sticky end An end of a double-stranded DNA molecule where there is a single-stranded
extension.
Stringent Refers to a plasmid with a low copy number of perhaps just one or two per cell.
Strong promoter An efficient promoter that can direct synthesis of RNA transcripts at
a relatively fast rate.
Stuffer fragment The part of a e replacement vector that is removed during insertion
of new DNA.
Supercoiled The conformation of a covalently closed-circular DNA molecule, which is
coiled by torsional strain into the shape taken by a wound-up elastic band.
Synteny Refers to a pair of genomes in which at least some of the genes are located at
similar map positions.
Taq DNA polymerase The thermostable DNA polymerase that is used in PCR.
T-DNA The portion of the Ti plasmid transferred to the plant DNA.
Temperature-sensitive mutation A mutation that results in a gene product that is functional
within a certain temperature range (e.g., at less than 30°C), but non-functional
at different temperatures (e.g., above 30°C).
Template A single-stranded polynucleotide (or region of a polynucleotide) that directs
synthesis of a complementary polynucleotide.
Terminator The short nucleotide sequence, downstream of a gene, that acts as a signal
for termination of transcription.
Terminator technology A recombinant DNA process which results in synthesis of the
ribosome inactivating protein in plant embryos, used to prevent GM crops from
producing viable seeds.
Thermal cycle sequencing A DNA sequencing method that uses PCR to generate chainterminated
polynucleotides.
Ti plasmid The large plasmid found in those Agrobacterium tumefaciens cells able to
direct crown gall formation on certain species of plants.
Topoisomerase An enzyme that introduces or removes turns from the double helix by
breakage and reunion of one or both polynucleotides.
Total cell DNA Consists of all the DNA present in a single cell or group of cells.
Totipotent Refers to a cell that is not committed to a single developmental pathway and
can hence give rise to all types of differentiated cell.
Transcript analysis A type of experiment aimed at determining which portions of a
DNA molecule are transcribed into RNA.
Transcriptome The entire mRNA content of a cell or tissue.
Transfection The introduction of purified virus DNA molecules into any living cell.
Transformation The introduction of any DNA molecule into any living cell.
Transformation frequency A measure of the proportion of cells in a population that are
transformed in a single experiment.