Glossary

Glossary

Genetic engineering technology

N.B. The following terms and definitions are for general educational purposes only.

Adenine (A) – a DNA base.

Agricultural biotechnology - a range of practices that encompasses traditional breeding techniques, alteringparts of or whole living organisms, improving plants or animals or developing micro-organisms for specific agricultural uses. Biotechnology includes genetic engineering technology.

Agrobacterium tumefaciens - a bacterium. It inserts its own DNA (transferred from its so-called tumour-inducing or Ti plasmid) into the host plant’s DNA. The inserted DNA produces growth hormones that result in a tumour. The tumour provides a habitat for the bacteria. This is an example of natural genetic engineering. The Ti plasmid can be used as a transformation vector in genetic engineering technology.

Allele - alternative genes that may occupy corresponding positions on each of a pair of chromosomes. A mutation, e.g. one that may be responsible for genetic disease, is an allele. Alleles can be dominant or recessive.

Allergen - a substance that provokes a hypersensitive reaction in the human body.

Amino acid - the molecular or structural building blocks for proteins. (See molecule and molecular biology.)

Atom – a particle too small to be divided. An atom consists of a positively charged nucleus, in which is concentrated most of the mass of the atom, around which revolve negatively charged electrons. Chemical atoms are the smallest particles in which elements combine with themselves or with each other.

Attenuated vector – micro-organisms or pieces of extra-chromosomal DNA (e.g. plasmids) that have infective components removed using recombinant DNA technology to destroy their virulence.

Bacillus – A rod-like bacterium, especially one of the various types that cause discease by entering and multiplying in animal and other tissues.

Bacterium (singular), bacteria (plural) – microscopic, prokaryote, single-celled organisms that may be infectious. Also bacterial.

Bacteriophage - any viruses that infect bacteria, also known as phage.

Base pair/s - there are four bases in DNA; some scientists think there may be more: (C) cytosine, (G) guanine, (A) adenine, and (T) thymine. Cytosine and thymine are pyrimidine bases. Adenine and guanine are purine bases. Cytosine is complementary to guanine. Adenine is complementary to thymine. If one strand of DNA has the sequence ATTGC then the complementary strand will be TAACG. Two complementary bases constitute a base pair. (In RNA, thymine is replaced by uracil.)

Biodiversity - the diversity or variety of living organisms in a particular environment.

Biopharming – using genetically engineered plants and domestic animals to produce pharmaceuticals, vaccines and antibodies; e.g.,using GE rice plants to produce a contraceptive.

Biotechnology - the industrial and agricultural use of biological processes, in particular molecular biology. It includes genetic engineering, human medicine, veterinary medicine, crop breeding, animal breeding, diagnostics, pharmaceuticals, forensics, and more. A term often used to describe genetic engineering or genetic modification, but genetic engineering is only one branch of biotechnology.

Bt (Bacillus thuringiensis) - a soil bacterium that produces an insecticidal protein or proteins. Different strains of Bt produce different proteins that present different effects. The Bt protein has been genetically engineered into crops so that they continually produce high concentrations of insecticidal proteins.

Cell - the smallest structural unit of all living organisms that can grow and reproduce independently. A cell is a mass of living material surrounded by a membrane (in plants and animals) and a wall (in plants only). It contains a nucleus, which houses most of the cell’s DNA. Cells can be classified as germ-line (sperm, egg cells) or somatic (rest of body tissues).

Cell line - a culture of cells that can be kept alive indefinitely in in vitro culture with a supply of appropriate of nutrients.

Chromosome – a microscopic linear structure containing thousands of genes (DNA) and located in the nucleus of a cell. A human being has 23 pairs of chromosomes in each somatic body cell: 22 are homologous (matching) pairs called autosomes. The two remaining CHROMOSOMES?? are sex chromosomes: two X chromosomes in females, and an X and a Y chromosome in males. One chromosome of each pair plus one sex chromosome come from the mother. The remaining 23 come from the father. Chromosomal - of the chromosome.

Clone - an exact duplicate of a fragment of DNA or an entire organism.

Cloning - the process of creating a clone.

Cloning vector - a DNA molecule that is capable of autonomous replication within a cloning host cell; e.g. E. coli. Cloning vectors are derived from bacteriophages, bacterial plasmids or viruses. They contain restriction enzyme sites for the insertion of foreign DNA.

Code - the sequence of DNA bases that forms the instructions for a given characteristic or trait in an organism.

Cross-pollination – the fertilization of one plant with pollen from another. Pollen can be transferred by wind, RAIN??, insects AND other organisms, humans AND VEHICLES??. Successful pollinations generally only occurs within a species, but in some cases can occur between two closely related species.

Cultivar - a particular cultivated variety of a plant.

Cytoplasm - that part of a cell that lies outside the nucleus.

Cytosine (C) – a DNA base.

Diploid - the presence of two chromosomes of a pair in a cell.

DNA - deoxyribonucleic acid, a large molecule that contains all genetic information in the cell and is composed of two complementary strands. Also see base pair/s, cytosine, guanine, adenine, and thymine.

cDNA - complementary DNA to a particular RNA fragment.

recombinant DNA / rDNA - DNA that has been cut and spliced back together in a new

sequence. The DNA may originate from one or more organism/s.

repetitive DNA - fragments of DNA that appear in multiple copies in a single individual.

Double-helix - the physical structure of DNA, comprising two parallel strands of DNA coiled helically.

E. coli (Escherichia coli) - a common intestinal bacterium. It is used in genetic engineering technology to act as a host for a cloning vector.

Element – a component part

Embryo – the early developmental stage of a plant or animal after fertilisation.

Endogenous – inside; internal.

Environment – surroundings

Enzyme - a protein involved in catalysing reactions in a cell.

Epigenetic factors - factors having an influence on the form, function or behaviour of an organism, originating outside of the genome.

Epistasis - interaction between genes.

Eugenics – the deliberate manipulation of the genetic makeup of human populations: by selective birth control, infanticide, mass murder or genocide. With the introduction of genetic engineering technology, eugenicists may use it for genetic screening, in vitro fertilisation plus pre-implantation screening, germ line genetic modification, etc.

Eukaryote - the major class of living things including all multi-cellular, higher organisms, and some single-celled organisms that have a nucleus in their cells containing chromosomes.

Exogenous – outside; external.

Field trial - testing a new technique or variety, including genetically engineered varieties, outside of the laboratory, but with specific requirements on location, size of plot, methodology, etc.

Foreign DNA, foreign gene – belonging to, proceeding from, other organisms; alien to.

Gametes - sperm, ova.

Gene - the basic unit of inherited traits; a segment of DNA that codes for a particular protein.

Gene cloning - the technique of making many copies of a gene.

Gene expression - the production by a cell of the protein or polypeptide for which the specific gene codes. Genes (DNA) are transcribed into a message (RNA) which in turn is translated into a polypeptide or protein that gives structural and metabolic features to a cell. (Also see metabolism, metabolite.)

Gene gun – a transformation technique that uses accelerated particles coated with DNA to introduce foreign DNA into a recipient organism.

Genetic modification – another term for genetic engineering.

Gene pair - corresponding genes in each of a pair of matching (homologous) chromosomes.

Gene pool - all the genes in a population at a given location. The size of the gene pool correlates to the genetic diversity of the population, i.e., a larger gene pool signifies a more biologically diverse population.

Genera – the plural of genus, a group of closely related species.

Gene silencing - the technological process/es whereby certain genes in a genome are prevented from being expressed. This may be by chemical or genetic modifications and/or other means.

Gene stacking – the introduction and accumulation of multiple traits in an organism.

Gene therapy – introducing new genes into individuals in order to cure diseases or genetic abnormalities. Genes may be added in a form that will be expressed in the somatic tissues or to the germ line cells.

Genetic code - the genetic information in DNA is encoded with four different nucleotide bases: A, C, G, and T. (See also base pair/s, Cytosine, Guanine, Adenine, and Thymine.

Genetic engineering – Also referred to as genetic modification and biotechnology. Changing a plant or animal for specific uses using genetic engineering technology. The manipulation of an organism’s heritable genetic material in the laboratory by introducing (via bacterial or viral vectors or by mechanical methods), eliminating or rearranging specific genes using modern molecular biology methods, particularly the practices referred to as recombinant DNA techniques. These include isolating, copying and multiplying genes, recombining genes or DNA from different species, and transferring genes from one species to another, bypassing the reproductive process. The term is usually reserved for in vitro recombinant DNA techniques.

Genetic fingerprinting - a technique that enables the identity of individuals or the genetic relationships between close relatives to be established.

Genetic map - the information of the relative positions of genes on chromosomes.

Genetic mutation – see Mutation.

Genome - the full set of chromosomes containing all the genetic material of a particular organism.

Genomics - the study of the structure and function of genomes.

Genotype – the total genetic information of an organism.

Genus - a group of closely related species. (See also genera.)

GEO, genetically engineered organism or GMO, genetically modified organism - an organism produced through genetic engineering (modification). An organism that has had incorporated in it a functional foreign gene or genes through the use of recombinant DNA technology. The novel gene/s exists in all of its cells and is passed through to progeny. (See transgenic.)

Germ line - sperm and egg cells (ova) and their precursors.

Germ line gene therapy - genetic manipulation of the sex cells (sperm, ova and their precursors).

GMO – genetically modified organism. (See GEO)

Growth hormone - a protein produced by the pituitary gland that promotes growth of the whole body. Growth hormones have been genetically engineered for human beings and animals.

Guanine (G) – a DNA base.

Haploid - a cell having half the usual number of chromosomes, e.g. sperm and ova.

Herbicide - a chemical compound used to kill weeds. Also Herbicidal.

Herbicide-tolerant crops - crops that have been changed either by genetic engineering or traditional breeding to survive applications of particular herbicides.

Heritable traits – contained in genes.

Horizontal gene transfer (HGT) – the transfer of genetic material from one organism to any other organism, not through sexual or asexual reproduction (vertical gene transfer).

Hormone - a chemical messenger that circulates in the blood, usually triggering some kind of physiological response.

Hybrid - the progeny of a cross between parents of different genetic types (sub-species, varieties or cultivars) or between different species.

Identity preservation (IP) - the segregation of one crop type from another at every stage from production and processing to distribution. IP is usually monitored through audits and site visits by an independent third-party.

Insecticide, insecticidal – a chemical compound used to kill insects.

Insecticide resistance - the engineering, development or selection of heritable traits in an insect population to allow individual plants to express the trait and survive the presence of an insecticide. Also the gradual build up of resistance to an insecticide by an insect pest.

Insect-resistant crops – crops engineered to withstand, deter or repel insects and thereby prevent them from feeding on the plant.

Insulin - a protein hormone secreted into the blood from the pancreas to control the amount of sugar in the blood. Human insulin is now produced in genetically engineered micro-organisms.

Intellectual property rights – (See patents.) The legal protection of inventions that include new technologies or new organisms (such as new GE plant varieties).

In vitro - a biological process conducted outside the body of a living organism. Literally translated, it means ‘in the glass’ - as in a test-tube.

In vivo - biological processes happening in a living organism.

Jumping genes - (see transposons.) Mobile genetic elements that move around genomes and which can transfer between organisms assisted by suitable carriers.

Locus/loci - the place/s on a chromosome occupied by a gene.

Marker gene - a gene, usually conferring antibiotic resistance, which is often detected by an in vitro culture bioassay or enzyme reaction. SHOULD WE ADD BIOASSAY???

Meiosis – the cell division or splitting by which means gametes (sperm, ova) are formed.

Messenger RNA (mRNA) - the RNA intermediate in protein synthesis. It contains a transcribed copy of the gene sequence that specifies the amino acid sequence of the polypeptide it encodes. (See transcription.)

Metabolism - the chemical processes that take place in living organisms leading to growth, development, and all other forms of energy transformation.

Metabolite - one particular chemical intermediate generated in metabolism.

Micro-organism - a microscopic organism.

Mitochondria - organelles in living cells found outside the nucleus and containing a small amount of the cell’s genetic material. Mitochondria have been called the “power house” of the cell. Mitochondria carry their own complement of DNA and are replicated independently. When a cell divides, each daughter cell receives half of the mitochondria.

Mitosis - cell division of somatic cells. Each daughter cell receives both chromosomes of each pair, the diploid state.

Mobile genetic element - (see transposons.)

Molecular biology: - the study of the proteins and nucleic acids that make up the living world, their structures and their relationships to biochemical activity, and the substances that are the repositories of genetic information, and the agencies for its communication from one generation to the next.

Molecular markers – detectable genetic traits that can be used to construct genetic maps, but which usually have no known function. (See heritable traits.)??

Molecule - the smallest unit of any chemical substance that has an independent, separate existence and that still retains the properties of the chemical substance. It is composed of atoms bonded together. Also molecular.

Monoculture – cultivating large areas of the same crop season after season.

Multigene families - genes that exist in multiple copies in the genome.

Mutagen - a substance or agent that causes genetic mutations, or chemical alteration of the genetic material, DNA.

Mutation - a spontaneous or induced genetic change in the genetic code (DNA) in an organism. A gene that has mutated is called a mutant. An organism containing an expressed mutant gene is also called a mutant. Most mutations are undesirable, but some can be very beneficial to breeders.

Novel – of a new kind, hitherto unknown; not previously existing in nature.

Nuclease - any enzyme that cuts nucleic acids. (See restriction enzyme.)

Nucleic acid - DNA or RNA.

Nucleic acid hybridisation - a process by which complementary strands of DNA or RNA will spontaneously match up with each other and bond together under the right conditions.

Nucleotide – the building block of DNA or RNA.

Nucleus - the organelle in the cell that contains the chromosomes. A structure in the eukaryote cell bounded by a membrane that contains the genetic material, in the form of DNA organized into chromosomes.

Organic agriculture – The practice of agricultural production that focuses on production without the use of synthetic inputs and does not allow the use of transgenic organisms.

Organism - an individual plant, animal or micro-organism that can independently carry out all life functions.

Outcrossing – the mating between different populations or individuals of the same species that are not closely related. Outcrossing can describe unintended pollination by an outside source of the same crop during hybrid seed production.

Parasite, parasitic – an organism able to invade another organism and draw nutrients from it.

Particle/s – a minute portion of matter; the smallest portion of matter.

Particle bombardment – the technique of using metal particles (often gold or tungsten) to blast DNA into cells for the purpose of genetic engineering (see gene gun).

Patent - intellectual property protection. A patent gives the owner the exclusive right to exploit an invention or biologically distinct line of an organism for a fixed period in exchange for full disclosure of how the invention is made. Users of the patented property may pay a royalty or technology fee for its use.

Pathogen – a biological agent that can cause disease.

PCR (Polymerase chain reaction) - a technique that allows specific amplification of particular minute DNA fragments.

Pesticide, pesticidal – a chemical compound able to kill pests.

Pest-resistant crops – plants engineered to withstand, deter or repel pests and thereby prevent them from damaging the plants. Plant pests can include insects, nematodes, fungi, viruses, bacteria, weeds, and others. Some plants may also be naturally resistant to pests without any form of genetic manipulation.

Phage - a virus that infects bacteria.

Phenotype - the observable characteristics of an organism due to genetic and environmental effects on development. (See genotype.)

Plasmid - a circular piece of DNA in bacteria that resembles the bacterial circular chromosome, but which is dispensable. Some bacterial strains contain many plasmids and some contain none. Plasmids are often used in genetic engineering as vectors.

Polygenic - controlled by or associated with more than one gene.

Polymer - a molecular chain, ring or web formed of units of smaller molecules, often repeating in an ordered pattern.

Polymerase - an enzyme linking the building blocks of a polymer to form the polymer.

Polypeptide - an amino acid chain, one or more of which are needed to make up a protein.

Polyploidy - the number of chromosomes in a cell. Most cells are diploid, i.e. they have two sets of chromosomes, but triploids, tetraploids and hexaploids are also not uncommon.

Primer - a segment of DNA that binds to a complementary strand of DNA. Primers are necessary to start the DNA polymerase enzyme and therefore are necessary in polymerase chain reaction (PCR).

Prokaryote - the class of organisms that do not have a nucleus in their cell. This includes all bacteria.

Promoter - a genetic sequence that switches on the expression of the new genes in the target cells.

Protease - an enzyme that cleaves proteins. SIMPLER WORD??

Protein/s - molecules composed of amino acids. Proteins constitute all enzymes and many of the structural components of an organism’s cells.

Provirus - a virus that has inserted its genome or a copy of its genome into the host cell genome.

Purine and pyrimidine – (See base pair/s.)

Recombinant - an organism containing a combination of alleles different from either parent. A DNA molecule containing a novel sequence of DNA. (See rDNA.)

Replication - the process whereby DNA makes copies of itself when a cell divides. The two strands of the DNA molecule unwind and each strand directs the synthesis of a new strand complementary to itself and identical to its former partner.

Resistant, resistance – exercising the ability to resist; taking on the ability to resist.

Restriction enzyme - a class of enzymes used to cut DNA at specific sequences called restriction sites. Restriction enzymes were strategic in making genetic engineering technology possible.

Retro-transposon - a mobile genetic element that depends on a reverse transcription step to move and to duplicate.

Ribose - a component of RNA.

Ribosomal RNA - RNA molecules that make up the ribosome.

Ribosome - an organelle in the cell required for protein synthesis.

RNA (ribonucleic acid) - forms of nucleic acid concerned with the synthesis of a protein.

RNA polymerase - an enzyme that makes RNA.

Selective breeding - deliberate crosses or matings of organisms to produce desired characteristics, derived from one or both of the parents, in the offspring.

Self-replicating – (See replication.) Able to replicate itself.

Sequence - the particular order of nucleotides in a DNA or RNA fragment. To determine the particular order of nucleotides in a strand of DNA. The same can be done for individual amino acids in a polypeptide or protein.

Somatic - body cells and tissues that do not include sex cells (sperm and ova and their precursors).

Species – the smallest unit of classification of living organisms commonly used, with the exception of sub species. A group of organisms whose members have the greatest mutual resemblance. A group of individuals that are able to breed among themselves.

Species barrier - a barrier believed to exist between one species and another that effectively precludes breeding between those species. In nature, similar species have interbred; e.g. the horse and the ass creating the mule.

Stem cell - a cell able to produce all the cells within an organism. Any accidental or engineered change in the genetic complement of a stem cell will pass on to progeny, by mitosis, and may be expressed in them.

Substantial equivalence - a non-scientific term to describe novel food crops produced by genetic engineering or modification technologies that have passed compulsory, regulatory tests for stability, nutritional properties and safety.

Superweeds - weeds tolerant to one or more herbicides.

Sustainable agriculture – any agricultural system that minimises the use of fuels and chemicals, and air, groundwater and soil pollutants, and which maintains soils that retain fertility for future generations. Permaculture, or sustainable farming which requires little or no external inputs, is seen as the pinnacle of this type of agriculture.

Terminator genes - genes used in terminator technology.

Terminator technology – the use of genetic engineering technology to create plants that produce sterile seeds.

Thymine (T) – a DNA base.

Traditional breeding – the development of plants and animals through selective breeding. Practices used in traditional plant breeding may include aspects of biotechnology such as tissue culture and mutational breeding. (See mutation.)

Transcription - the process of making a complementary sequence of the gene sequence in the genome. Copying of genetic information from DNA to messenger RNA (mRNA).

Transduction - the transfer of genes by viruses from one organism to another.

Transformation - the process of incorporating foreign DNA into an organism.

Transgene - a foreign gene incorporated by transformation. Chosen genetic information.

Transgenic - an organism genetically engineered with DNA that is foreign to that organism; transgenesis.

Translation - protein synthesis; the conversion of information from mRNA into a protein.

Transposons - mobile genetic elements that move around genomes and which can transfer between organisms assisted by suitable carriers.

Uracil – a component of RNA, replacing thymine in the base pairs.

Variety - a subdivision of a species for taxonomic (DESCRIPTION??) classification, sometimes referred to as a cultivar (cultivar is short for cultivated variety). A variety is a group of individual plants that is uniform, stable, and distinct genetically from other groups of individuals in the same species.

Vector – a carrier for a cassette of genetic material. Created to invade the genome of a new host in order to insert foreign DNA sequences into it.

Virus - an infectious parasitic organism, which can only replicate in a host cell. Viruses carry DNA or RNA in a protein coat. Some engineered viruses are used in research to deliver foreign gene/s into cells, exploiting their ability to infect cells (see virus vector). A virus’ genetic material can become integrated into a cell’s genome to form a provirus.

Virus vector - a virus used as a carrier for a gene when making an engineered organism.

Xenotransplantation – the transplantation of organs or the grafting of genetic material (xenografts) from animals to human beings. Donor animals will be genetically engineered to avoid rejection.