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The glossary gives brief definitions of terms commonly used in the study of bioscience and technologies associated with gene technology.

It is not intended to provide comprehensive and detailed descriptions and explanations - you will need to refer to your text or other reference materials for these.

Allele	Homologous pairs of chromosomes contain the same sets of genes at the same loci but there can be different alternatives eg gene for a particular trait occupies the same locus on each chromosome but there might be different versions (A and a). Each version is called an allele.
Amino acid	Organic molecules from which protein molecules are built. There are 20 different kinds of amino acids.
Base	Component of a nucleotide unit composed of a phosphate, sugar and base held together by hydrogen bonds. There are four different bases: Adenosine (A), Cytosine (C), Thymine (T) and Guanine (G). These nucleotides are common to all known forms of life. Pairing of bases follows the 'base-pairing rule': A pairs with T, C pairs with G.
Bioactives	Specific proteins (eg in milk) that have useful properties and will be used in the development of nutraceuticals and pharmaceuticals.
Bioinformatics	The branch of computer science that deals with the collection, organisation, analysis or interrogation of biological information, particularly genetic information. It also involves the use of 3-D modelling of biological molecules (biomolecules) and biologic systems.
Biotechnology	Tools, techniques and processes that use living organisms or biological systems to modify processes or products for particular purposes. Commonly applied to but not limited to genetic modification.
Blastocyst	A hollow ball of cells in the early stage of development of an embryo prior to its implantation in the wall of the uterus.
Cell	Smallest functional unit of a living thing. Organisms can be unicellular, multicellular or colonial.
Cell biology	The study of the structure and functioning of cells.
Cell division	Process by which cells divide into two (sometimes but inaccurately, referred to as mitotic division). Parent cell divides into two daughter cells: mitotic division of the nucleus to produce diploid cells, meiosis to produce haploid gametes.
Chromosome	Coiled protein-coated strand of the DNA molecule found in the cells of eukaryotic organisms. In non-dividing cells the chromosomes are equivalent to one chromatid; in dividing cells the chromosome consists of two identical chromatids.
Cloning (molecular/gene/cell)	Process of making an identical copy of a molecule, gene or cell.
Cloning (organism)	Process of making a copy of an organism identical to the parent: in sexually reproducing organisms for example by nuclear transfer or by embryo splitting, or asexually for example by grafting or cuttings.
Conventional breeding	Natural process of producing new organisms asexually or sexually.
Differentiation	Process by which undifferentiated cells become specialised to carry out a particular function.
DNA	Molecules of deoxyribonucleic acid measured in kilobases (kb). Coding regions of the DNA molecule (exons) are separated by non-coding regions (introns).
DNA probes	A DNA probe is a small fragment of known DNA sequence (synthesised or natural) that will be attracted to a complementary 'target' sequence in DNA fragments. A fluorescent tag on the probe shows up in the gel when exposed to UV light or a radio-active tag is used and shows on a photographic film.
DNA profiling	A process by which variations in an individual's DNA, caused by repeats of sequences of a few base pairs (Short Tandem Repeats or microsatellites), are identified. DNA profiling can be accomplished using techniques of PCR and gel electrophoresis or using DNA probes and Southern Blotting.
Embryo	Organism at the stage of development before organs appear.
Embryo splitting	Process by which clones of animals with favoured characteristics are formed. An egg is fertilised in a petri dish and divides into two. Each cell is treated to develop separately. At an early stage of development they are implanted into surrogate mothers.
Exon	Component of the part of the DNA molecule (gene) that codes for the production of proteins.
Foetus	The stage of the organism, after the embryo, in which distinct organs develop (in humans at about eight weeks).
Gel electrophoresis	Technique of separating fragments of DNA, produced by the action of restriction enzymes.
Gene	Unit of heredity. Segment of DNA that carries the code for producing a protein molecule but possibly for other molecules too. Single genes might affect the development of a particular characteristic; many genes might be involved in the development of a particular characteristic.
Gene chip	Gene chips contain thousands of known gene probes which target genes in samples of material that the chip is exposed to.
Gene expression	Describes the process by which a gene is actively producing its products, whether proteins or RNA; often called protein synthesis. Two stages are evident: transcription (DNA to mRNA) and translation (mRNA to formation of polypeptide chains).
Gene mapping	Process of locating the position of genes along chromosomes.
Gene marker	A known DNA sequence used to identify the location (locus) of a particular gene on a chromosome.
Gene pool	Collective term that describes the sum of all the genes in a population of a species. In addition to microevolutionary processes (mutations, natural selection, gene flow by immigration, emigration), gene pools can be affected by deliberate manipulation of genes eg changing the genomes of cattle herds.
Gene silencing	Process of inactivating a gene using the technique of creating 'short interfering RNAs (siRNAs) that combine with a gene's messenger RNA. This prevents it from conveying instructions to make a particular protein.
Gene switching	Technique of activating or de-activating a gene.
Gene technology	Term that describes the techniques and processes involved in manipulating the genetic make-up of organisms (genetic engineering).
Gene therapy	The application of gene technology to correct genetic defects and disorders.
Genetics	Broad term that describes the study of genes and inheritance.
Genetic code	The arrangement of nucleotides in three-letter codons. Each codon represents instructions for the production of one amino acid. Several codons might code for the production of a particular amino acid, the difference being in the final or third nucleotide of the codon.
Genetic diversity	The variety of different genes, including alleles, within a population or species that contribute to variation in members of that species.
Genetic engineering	Another term for gene technology by which tools and techniques are used to alter the genetic makeup of organisms for particular purposes.
Genetic manipulation	Deliberately altering in some way the genetic make-up of an organism. This could be by the application of gene technology, by selective breeding or by using certain reproductive technologies.
Genetic modification	Process by which an organism's DNA is altered artificially in some way by removing or switching off a gene, altering an existing gene or adding a foreign gene.
Genetically modified organism (GMO)	An organism that has been altered by switching off genes or the addition or removal of genes.
Genome	The entire set of genetic material required for a particular organism to develop. Each species has its own particular genome that might resemble but not be the same as, the genomes of other species.
Genomics	The study of genomes, the functions of genes and their interactions.
Genotype	The genetic make-up of an organism.
Germ cell/gamete	Haploid reproductive cell of an organism.
Hybrid	Describes an organism produced as a result of interbreeding between members of different species. Also describes recombinant DNA.
Inheritance	Passing on of characteristics or traits from one generation to the next.
IP (intellectual property)	Refers to the intellectual thinking and creations of the mind that are then represented in inventions, designs, names, symbols, images, texts, art forms etc. IP can be bought, sold, or licensed just like any other property. IP is in two categories: industrial property (inventions, trademarks, etc), and copyright (literary and artistic works, architectural designs).
Intron	Non-coding part of the gene, removed during formation of the mRNA.
Issue	An event, development or matter of concern that is controversial ie about which people and organisations have different points of view.
Ligases	Particular enzymes that join the cut ends of DNA resulting from the action of restriction enzymes.
Microarray	Gene microarrays are collections of genes embedded in computer chips. They enable us to look at tens of thousands of genes in a single experiment (see gene chip).
Micro-chip	General term for very small computer chips that can carry large amounts of information (data).
Nuclear transfer	Process of transferring nuclear material from a donor (somatic) cell to the recipient cell (oocyte) that has had its nucleus removed. Used in cloning organisms.
Nucleotide	Basic unit of DNA consisting of a base, sugar and phosphate held together by hydrogen bonds.
Nucleus	Control centre of the cell in eukaryotic organisms. Consists of nucleic acids surrounded by the nuclear membrane.
Nutraceutical	A food product with nutritional value. Term is also applied to a product with improved pharmaceutical properties. Can be produced by genetic modification.
Oocyte	An egg cell.
Organism	A living or once-living thing.
Patent	A patent is the exclusive right granted by a patent office to use an invention: new product or process that provides a new way of doing something or is a new way to solve a problem. Patents can be bought, sold or licensed - like anything else that is owned.
PCR (polymerase chain reaction)	Technique of amplifying (making more of) sequences of a DNA molecule.
Phenotype	Characteristics evident in an organism (structural, physiological) resulting from the interaction between an organism's genotype and environmental conditions.
Process	General term that describes the means of achieving a particular purpose, possibly involving a number of techniques.
Protein	Complex organic compound consisting of molecules of C,H,O and N, forming long and complex polypeptide chains.
Protein synthesis	Process in living cells by which proteins are produced, in two distinct stages (transcription and translation) as a result of gene activity.
Proteome	The collective term for all the proteins produced by an organism.
Proteomics	The study of proteins (gene products) and their interactions.
Recombinant DNA	'Recombined' DNA - hybrid DNA that is produced as a result of combining DNA from different organisms.
Recombinant DNA technology	Techniques and tools used to produce recombinant or hybrid DNA.
Reproductive technologies and embryology	Technologies developed to increase the reproductive capabilities of organisms. These include in vitro fertilisation (IVF), artificial insemination (AI) and embryo implantation.
Restriction enzymes (endonucleases)	Naturally occurring enzymes (isolated from bacteria) that are able to cut DNA molecules at particular sites. Now used in a controlled way as a technique to cut DNA at specific recognition sites. The cutting leaves ends that could be joined together.
RNA (ribonucleic acid)	The 'sense' strand of DNA is copied to make RNA, a template for making proteins. mRNA is a copy of the DNA molecule, less the introns. 'Antisense' RNA is made from the complementary strand of DNA and can bind to 'sense' RNA and block protein production, also possibly to regulate gene activity.
Sequencing	Process by which the order of nucleotides along a segment of DNA or RNA is determined. This provides information about the genes present which in turn enables sequencing of amino-acids, the building units of proteins.
Somatic cell	Diploid body cell as opposed to germ or reproductive cell (gamete).
Species	Organisms with such a high level of similarity that they are considered to be the same. If the organism reproduces sexually, then those that are generally capable of interbreeding to produce fertile offspring are considered to be of the same species.
Stem cells	Stem cells are early-stage cells, generally of two types, that have not become differentiated: embryonic stem cells (ES cells) are collected (harvested) from blastocysts, adult stem cells (AS cells) are collected from a few kinds of specialised (differentiated) tissues eg bone marrow, skin, intestine, umbilical cord. Stem cells can potentially produce other types of cells.
Technique	A procedure or methodology that requires the use of instruments, tools or machines.
Technology	Collective term describing use of techniques, instruments or machines for a particular purpose.
Trait	A characteristic or feature (structural, physiological) of an organism.
Transcription	Stage in the process of protein synthesis during which the coding strand of DNA is the template for producing messenger RNA (mRNA).
Transgenesis/transformation	Process of inserting a favoured gene from an organism of one species into the genome of an organism of another species using one of a variety of techniques such as pro-nuclear micro-injection or ballistic DNA injection.
Transgenic organism	Organism, containing foreign DNA, produced as a result of transgenesis (or transformation).
Translation	Stage in the process of protein synthesis during which mRNA controls the production of polypeptide chains. In eukaryotic cells the mRNA moves from the nucleus into the cytoplasm where translation takes place. In prokaryotic cells the chromosomes are in the cytoplasm, not contained in a nucleus.
Vector	An agent that transfers or delivers a gene into the cells of an organism. Viral vectors are infectious agents such as an adenovirus (eg modified to carry the normal cystic fibrosis gene into the cell), retroviruses that integrate genes into the chromosome of the host cells, possibly randomly. Liposomes are tiny fat globules in which genes can be enclosed. These vectors fuse with the plasma membrane and deliver the genes into the cells. Plasmid vectors are naturally occurring micro-organisms such as bacteria whose plasmids can be treated to carry the desired gene (segment of DNA) into host cells.
Zygote	Diploid cell resulting from the fusion of two haploid gametes.

 

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