Common terms used in plant genetics

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B
C
D
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F
G
H
I
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M
N
O
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Z

A
Agrobacterium tumefaciens: A bacterium used in the process of genetic modification. Agrobacterium tumifaciens causes crown gall disease in plants and is used as a vector to introduce DNA into plant tissue
Allele: A particular form of a gene. Each allele has a slightly different sequence of DNA bases but the same overall structure. Alleles usually occur in pairs - one on each chromosome. When both alleles are the same, the individual is described as being a homozygote. When each allele is different the individual is described as being heterozygote.
Allergen: A substance (usually a protein) that triggers an allergic reaction in a susceptible person or animal.
Amino acid: see protein
Antibiotic: A chemical that kills or inhibits the growth of micro-organisms and is used in treating disease.
Antibiotic marker gene: A gene that codes for resistance to an antibiotic. Used to identify when gene transfer has been successful. Following the genetic engineering process, the cells are grown in a medium containing the relevant antibiotic. Only the cells that have been successfully transformed will be able to survive.
Antisense gene: Insertion, by genetic engineering, of a gene in a reverse or backwards orientation. The antisense gene interferes with the operation of the same gene naturally found in the organism. This approach has been used to switch off, delay or slow down the operation of natural process such as softening in tomatoes and other fruits.
Arabidopsis thaliana: A plant species with the common name 'thale cress'. It has a very small genome with only 5 chromosomes so is used extensively in experimental studies.
B
Bacillus amylioliquefaciens: A bacterium found in soil often genetically modified to produce enzymes for industrial purposes.
Bacteria(pl. Bacterium): Unicellular or, rarely, multicellular organisms. Bacteria have various shapes, occurring as cocci (spherical), bacilli (rod-shaped) and spirilla (helical) which range in size from 1m m to about 50m m, but usually 1-10m m in diameter. They are present in soil, water and air. Many are important in natural processes such as decomposition, some can cause diseases.
Bacteriophage: A virus that is parasitic within a bacterium. Phages are used experimentally to identify bacteria, to control manufacturing processes (such as cheese production) that depend on bacteria and, because they can alter the genetic make-up of bacterial cells, they are important tools in genetic engineering as cloning vectors. Each phage is specific for only one type of bacterium.
Base pair (bp): A pair of the complementary bases making up DNA. In the spiral ladder (double helix) structure of DNA, adenosine always pairs with thymine and cytosine with guanine. The size of genes or genomes is often measured by the number of base pairs they contain.
Biolistics: The use of a 'gene gun' to genetically engineer plants, particularly grain crops such as maize, rice and wheat. DNA is coated onto to microscopic gold particles which are then fired into cells. In some cases the DNA is taken up and incorporated into the genome of the cell. Marker genes are used to identify when the process has been successful.
Biotechnology: The use of biological methods in industrial production. Traditional biotechnology includes wine, bread, cheese and yoghurt making. Genetic engineering uses biological methods so is also a form of biotechnology. Sometimes genetic engineering is called the 'new biotechnologies'.
BNYVV: Beet Necrotic Yellow Vein Virus. This virus of sugar beet is transmitted by a soil fungus, Polymyxa betae. It is responsible for the disease called Rhizomania which is a serious agricultural problem.
BST: Bovine somatotropin - a hormone (also known as bovine growth hormone or BGH) that stimulates milk production in cows. BST has been produced by genetically engineered bacteria and is used in the US and elsewhere to increase the milk production. It is not allowed in Europe.
Bt toxin: A toxin produced by the bacteria Bacillus thuringiensis. Specific strains of Bacillus thuringiensis produce slightly different types of the toxin which are damaging to certain species of insect. The gene to produce the toxin is used in genetic engineering of crop plants to make them resistant to insects. Bacillus thuringiensis is also used as a biological control agent by organic farmers.
BWYV (BMYV): Beet Western Yellow Virus (Beet Mild Yellowing Virus). This virus is transmitted by two aphids, Myzus persicae and Macrosiphum euphorbiae. This disease is a major problem for the commercial growing of sugar beet.
C
Chimeric gene: A gene or DNA sequence which is not found in nature but which has been constructed in a laboratory. This includes genes which have only been slightly altered from their original form
Chromosome: Chromosomes carry the genetic material of an organism. They are coiled structures found in the nucleus of eukaryotic cells and are made up of DNA .Each species has a typical number of chromosomes (eg 46 in humans, 20 in maize) which come in identical pairs with one of each pair coming from each parent. In viruses, the chromosomal material can be DNA or RNA.
Constitutive promoter: A promoter which will have a gene 'switched on' in every cell in the plant. That is to say that the product of the gene will be produced by every cell in the plant.
Crop Line: A collection of plants of one species of one variety and are often genetically identical. Plants within a crop line will grow, and respond to the environment in exactly the same way as others of that line.
D
DNA: Deoxyribonucleic acid (DNA) is the chemical that makes up the chromosomes of almost all organisms. It contains the genetic information for cell structure, function and organisation. The DNA is made up of four bases, adenosine (A), cytosine (C), guanine (G) and thymine (T) which form two complementary chains in a spiral ladder (double helix) formation. A always pairs with T and G with C. The DNA forms a code using triplets. Each triplet e.g. AAC, CCG, ATT, codes for one amino acid which are molecules that, joined together, form proteins. Also see base pairs (bp)
Donor organism: The organism which donates genes from the host organism during genetic engineering.
Down regulation: The use of an introduced gene to reduce the activity of a naturally occurring gene. Often uses 'sense' or 'anti-sense' genes.
E
Escherichia coli (E.coli): A bacterium found in the intestine of animals and humans. Used extensively in genetic engineering. Some strains can cause disease, the majority are harmless.
Eukaryotes: An organism in which the genetic material is contained within a distinct nucleus. All organisms except bacteria are eukaryotes.
Exon: A nucleotide sequence (of DNA or RNA) in a gene that codes for part or all of the gene product or for some control function. In eukaryotes, exons are separated by non coding sequences called introns.
F
Fungicide: Any chemical which kills fungi.
Fungi: A group of organisms formerly regarded a simple plants lacking chlorophyll but now classified in a separate kingdom. They can either exist as single cells or make up a multicellular body called a mycelium, which consists of filaments known as hyphea. Most fungi are either parasites or saprophytes (live of dead things) on other organisms.
G
Gene: The basic unit of heredity that transmits information from one generation to another. Genes consist of specific sequences of DNA nucleotides which code for the construction of a particular protein.
Gene cassette: Consists of the functional gene plus its regulatory genes and introns etc.
Gene cloning: The production of exact copies (clones) of a particular gene or genes using genetic engineering techniques. Gene cloning facilitates gene sequencing; it also enables large quantities of a desired protein product to be produced: human insulin, for example, is now produced by bacteria containing the cloned insulin gene.
Gene construct: A sequence of genes made by joining several genes together artificially in the laboratory.
Gene expression: When a gene operates or is switched on in an organism it is said to be expressed.
Gene gun: see biolistics
Gene sequence: The order of the bases pairs (bp) in DNA making up a gene or genes.
Gene splicing: A stage in the processing of messenger RNA, occurring only in eukaryotic cells, in which noncoding introns are removed from the primary mRNA transcript and the coding exons are spliced together to form the functional mRNA molecule.
Gene stacking: When several different traits are genetically engineered into a plant or other organism. For example, some crops are genetically engineered to be tolerant to a herbicide and also to be insect resistant.
Genetic code: The sequence of nucleotide bases pairs (bp) in DNA are read in triplets (codons). Each codon is responsible for the placing of one amino acid in the polypeptide chain during translation. This code appears to be universal across all species from bacteria to mammals.
Genetic engineering: The techniques involved in altering the characters of and organism by inserting genes from another organism into its DNA. This altered DNA (known as recombinant DNA) is usually produced by gene cloning.
Genetic modification: An alternative term for genetic engineering.
Genome: The complete genetic material of a cell.
Genomics: The study of the genome - to establish its sequence and function.
Glufosinate: A broad spectrum, contact herbicide made by AgrEvo (now part of Aventis). Marketed under various trade names including Liberty and Basta. Many crops have been genetically engineered to be resistant to its effect so a farmer can spray a crop with glufosinate, killing the weeds but leaving the crop unharmed. The system is known as 'Liberty Link'.
Gluphosinate: See glufosinate ammonium.
Glyphosate: A broad spectrum, systemically acting (the chemical is taken into the plant and distributed though out it) herbicide made by Monsanto. Marketed under the trade name 'Roundup'. Many crops have been genetically engineered to be resistant to its effect so a farmer can spray a crop with glyphosate, killing the weeds but leaving the crop unharmed. The system is known as 'Roundup Ready'.
H
Herbicide: Any chemical weed killer. Herbicides can be selective, killing only a specific range of plants or they can be broad spectrum herbicides killing a much wider number species.
Herbicide tolerance: When a plant has been genetically engineered to tolerate the effects of a herbicide (weedkiller). A farmer can spray a crop with the herbicide, killing the weeds but leaving the crop unharmed.
Heterozygote: See allele.
Homozygote: See allele.
Host organism: The organism into which the genes are being transferred from the donor organism
Hybrid: A crop line produced by crossing two genetically different parents. The offspring often show 'hybrid vigour' with better yields than either of the parent plants.
I
Insect resistance: When a plant has been genetically engineered to be resistant to insects. Often done by introducing a gene for an insecticidal toxin into the plant such as the toxin gene from Bacillus thuringiensis (Bt toxin) or a lectin gene from the snowdrop.
Insecticide: Any chemical which kills insects. They can be toxic to all insects (e.g. pyrethrum) or a specific group.
Intron: 'Intervening sequence' A nucleotide sequence in a gene that does not code for the gene product. Introns, which are only found in eukaryotes, are transcribed into messenger RNA but are subsequently removed from the transcript before translation. Their functional significance is controversial.
J
K
L
Liberty: See glufosinate ammonium.
M
Marker gene: A marker gene has a characteristic that can be selected for in the laboratory. They are used in genetic engineering to identify when the foreign genes have been successfully integrated into the host organism. Marker genes include antibiotic resistance, genes that cause fluorescence and others that trigger colour changes (e.g. the GUS gene).
Micro-organism: An organism which cannot be seen with the naked eye. These include bacteria, viruses and yeasts.
N
National Seed Listing: Before a seed variety can be sold in the UK it is necessary for it to be placed on the national seed list. This requires the variety going through a series of trials to determine its stability, distinctiveness and uniformity. The theory is that this maintains a high standard of seed from which farmers and other growers can choose from.
Nucleus: The structure or 'organelle' within plant and animal cells which contains the chromosomes
O
P
Patent: A patent is a monopoly right to the commercial exploitation of an invention for a period of 17-20 years. In exchange, the patent holder publishes information about the invention. A patent must fulfil three criteria: novelty (not obvious); inventive (not a discovery) and utility (can be practically used) Since the introduction of genetic engineering, genes, cells and organisms have become patentable.
Pesticide: A general term for fungicides, insecticides and herbicides.
Phenotype: The observable characteristics of an organism such as hair or eye colour in humans and flower colour and size in plants.
Phosphothrinocin: see glufosinate ammonium.
Plasmid: A circular length of DNA found in bacteria that replicates independently of the chromosomes. It plays an important role in gene transfer and in infection. Their relatively simple structure and the ability of some plasmids to transfer DNA into an organisms' genetic material, makes them widely used in genetic engineering.
Polypeptide: See protein
Prokaryote: Any organism belonging to the kingdom Prokaryotae (or Monera), in which the genetic material is not enclosed in a cell nucleus. Bacteria are prokaryotes.
Promoter: The key control element that triggers a gene to operate through the production of mRNA.
Protein: Proteins are complex molecules that are the basic building blocks of cells. Protein molecules consist of one or several long chains of amino acids (polypeptides) linked in a characteristic sequence. These polypeptides undergo coiling and pleating, to create a characteristic shape. Both the amino acid sequence and the final shape of the protein determine the many crucial roles that they play in living organisms.
Q
R
recombinant DNA (r DNA) technology.: Another term for genetic engineering.
Regulator gene / Regulatory sequence: Includes promoter, terminator and other genes that control the expression of a gene. They determine when a gene operates (is switched on or off) and which cells in an organism the gene is expressed.
Restriction enzymes: Enzymes used in the process of genetic engineering that cuts DNA at specific sites - a sort of molecular scissors.
Ribosome: A small spherical body within a living cell which consists of a type of RNA called ribosomal RNA and protein. There are usually many ribosomes in a cell.
RNA: A molecule involved in translating the DNA code into protein synthesis. It is formed of a long chain of four bases - cytosine, guanine, adenine and uracil. Messenger RNA (mRNA) carries the genetic code from the DNA to specialised sites in the cell known as ribosomes. Ribosomal RNA (rRNA) is present in the ribosomes and transfer RNA (tRNA) is involved in the protein assembly process at the ribosomes
Roundup: see glyphosate
S
Selectable marker gene: see marker gene.
Sense gene: Insertion of a gene, by genetic engineering, in the same orientation as a gene found naturally in an organism. It interferes with the normal functioning of a gene. It has been used in systems to delay ripening of fruits.
Streptomyces hygroscopicus: A soil bacterium often used in genetic engineering.
T
T-DNA: 'transferred' DNA - DNA transferred using genetic engineering. T-DNA is part of a plasmid, at one end is the left border at the other the right border.
Terminator: A DNA sequence that switches off the operation of a gene.
Ti-plasmid: A 'tumour-inducing' plasmid with the ability to transfer DNA from the plasmid into the host genome. Ti plasmids are found in Agrobacterium tumifacienes and non-virulent forms are commonly used in plant genetic engineering to transfer genetic material.
Trait: An observable characteristic such as colour, herbicide tolerance etc.
Transformation: The process of actually putting the foreign genes into a new species. Each time this is done it is called a transformation event.
Transcription: The process in living cells in which the genetic information of DNA is transferred to a complementary strand of messenger RNA (mRNA) as the first step in protein synthesis. Transcription takes place in the cell nucleus or nuclear region and the mRNA moves to the protein production site in the ribosome.
Transgene(s): The gene(s) transferred into another organism using genetic engineering.
Transgenic organism: An organism that contains foreign genes created by the use of genetic engineering.
Translation: The process of translating the code in messenger RNA (mRNA) into protein production in the ribosome.
Truncated gene: A gene which has been shortened, that is some of the base pairs (bp) have been removed. Truncated genes may or may not function differently from their full length counterparts depending on which and how many base pairs have been removed.
U
V
Vector: A piece of DNA that can incorporate foreign DNA and transfer it between organisms.
Virus: A organism that is too small to be seen with a light microscope but is capable of independent metabolism and reproduction within a living cell. A mature virus (a virion) ranges in size from 20 - 400 nm in diameter. It consists of core of nucleic acid (DNA or RNA) surrounded by a protein coat (capsid). Some bear an outer envelope (enveloped viruses). Inside its host cell the virus initiates the synthesis of viral proteins and undergoes replication. The new virions are released when the host cell disintegrates. Viruses are parasites of animals, plants, and some bacteria (known as bacteriophages).
W
X
Xeno-transplantation: The use of animal organs for transplantation to humans. Animals are being genetically engineered to look more human to the immune system and thus decrease the likely hood of rejection. There are concerns about the potential for disease causing viruses to be transferred.
Y
Yeast: A group of unicellular cellular fungi of the class Hemiascomycetae and phylum Ascomycota. They occur as single cells or as groups or chains of cells. They reproduce both sexually and asexually. Yeasts of the genus Saccharomyces ferment sugars and are hence used in baking and brewing. Mans ability to and long history of culturing yeasts has made them useful tools in genetic engineering.
Z

Common terms used in plant genetics

A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z

A
Agrobacterium tumefaciens: A bacterium used in the process of genetic modification. Agrobacterium tumifaciens causes crown gall disease in plants and is used as a vector to introduce DNA into plant tissue
Allele: A particular form of a gene. Each allele has a slightly different sequence of DNA bases but the same overall structure. Alleles usually occur in pairs - one on each chromosome. When both alleles are the same, the individual is described as being a homozygote. When each allele is different the individual is described as being heterozygote.
Allergen: A substance (usually a protein) that triggers an allergic reaction in a susceptible person or animal.
Amino acid: see protein
Antibiotic: A chemical that kills or inhibits the growth of micro-organisms and is used in treating disease.
Antibiotic marker gene: A gene that codes for resistance to an antibiotic. Used to identify when gene transfer has been successful. Following the genetic engineering process, the cells are grown in a medium containing the relevant antibiotic. Only the cells that have been successfully transformed will be able to survive.
Antisense gene: Insertion, by genetic engineering, of a gene in a reverse or backwards orientation. The antisense gene interferes with the operation of the same gene naturally found in the organism. This approach has been used to switch off, delay or slow down the operation of natural process such as softening in tomatoes and other fruits.
Arabidopsis thaliana: A plant species with the common name 'thale cress'. It has a very small genome with only 5 chromosomes so is used extensively in experimental studies.
B
Bacillus amylioliquefaciens: A bacterium found in soil often genetically modified to produce enzymes for industrial purposes.
Bacteria(pl. Bacterium): Unicellular or, rarely, multicellular organisms. Bacteria have various shapes, occurring as cocci (spherical), bacilli (rod-shaped) and spirilla (helical) which range in size from 1m m to about 50m m, but usually 1-10m m in diameter. They are present in soil, water and air. Many are important in natural processes such as decomposition, some can cause diseases.
Bacteriophage: A virus that is parasitic within a bacterium. Phages are used experimentally to identify bacteria, to control manufacturing processes (such as cheese production) that depend on bacteria and, because they can alter the genetic make-up of bacterial cells, they are important tools in genetic engineering as cloning vectors. Each phage is specific for only one type of bacterium.
Base pair (bp): A pair of the complementary bases making up DNA. In the spiral ladder (double helix) structure of DNA, adenosine always pairs with thymine and cytosine with guanine. The size of genes or genomes is often measured by the number of base pairs they contain.
Biolistics: The use of a 'gene gun' to genetically engineer plants, particularly grain crops such as maize, rice and wheat. DNA is coated onto to microscopic gold particles which are then fired into cells. In some cases the DNA is taken up and incorporated into the genome of the cell. Marker genes are used to identify when the process has been successful.
Biotechnology: The use of biological methods in industrial production. Traditional biotechnology includes wine, bread, cheese and yoghurt making. Genetic engineering uses biological methods so is also a form of biotechnology. Sometimes genetic engineering is called the 'new biotechnologies'.
BNYVV: Beet Necrotic Yellow Vein Virus. This virus of sugar beet is transmitted by a soil fungus, Polymyxa betae. It is responsible for the disease called Rhizomania which is a serious agricultural problem.
BST: Bovine somatotropin - a hormone (also known as bovine growth hormone or BGH) that stimulates milk production in cows. BST has been produced by genetically engineered bacteria and is used in the US and elsewhere to increase the milk production. It is not allowed in Europe.
Bt toxin: A toxin produced by the bacteria Bacillus thuringiensis. Specific strains of Bacillus thuringiensis produce slightly different types of the toxin which are damaging to certain species of insect. The gene to produce the toxin is used in genetic engineering of crop plants to make them resistant to insects. Bacillus thuringiensis is also used as a biological control agent by organic farmers.
BWYV (BMYV): Beet Western Yellow Virus (Beet Mild Yellowing Virus). This virus is transmitted by two aphids, Myzus persicae and Macrosiphum euphorbiae. This disease is a major problem for the commercial growing of sugar beet.
C
Chimeric gene: A gene or DNA sequence which is not found in nature but which has been constructed in a laboratory. This includes genes which have only been slightly altered from their original form
Chromosome: Chromosomes carry the genetic material of an organism. They are coiled structures found in the nucleus of eukaryotic cells and are made up of DNA .Each species has a typical number of chromosomes (eg 46 in humans, 20 in maize) which come in identical pairs with one of each pair coming from each parent. In viruses, the chromosomal material can be DNA or RNA.
Constitutive promoter: A promoter which will have a gene 'switched on' in every cell in the plant. That is to say that the product of the gene will be produced by every cell in the plant.
Crop Line: A collection of plants of one species of one variety and are often genetically identical. Plants within a crop line will grow, and respond to the environment in exactly the same way as others of that line.
D
DNA: Deoxyribonucleic acid (DNA) is the chemical that makes up the chromosomes of almost all organisms. It contains the genetic information for cell structure, function and organisation. The DNA is made up of four bases, adenosine (A), cytosine (C), guanine (G) and thymine (T) which form two complementary chains in a spiral ladder (double helix) formation. A always pairs with T and G with C. The DNA forms a code using triplets. Each triplet e.g. AAC, CCG, ATT, codes for one amino acid which are molecules that, joined together, form proteins. Also see base pairs (bp)
Donor organism: The organism which donates genes from the host organism during genetic engineering.
Down regulation: The use of an introduced gene to reduce the activity of a naturally occurring gene. Often uses 'sense' or 'anti-sense' genes.
E
Escherichia coli (E.coli): A bacterium found in the intestine of animals and humans. Used extensively in genetic engineering. Some strains can cause disease, the majority are harmless.
Eukaryotes: An organism in which the genetic material is contained within a distinct nucleus. All organisms except bacteria are eukaryotes.
Exon: A nucleotide sequence (of DNA or RNA) in a gene that codes for part or all of the gene product or for some control function. In eukaryotes, exons are separated by non coding sequences called introns.
F
Fungicide: Any chemical which kills fungi.
Fungi: A group of organisms formerly regarded a simple plants lacking chlorophyll but now classified in a separate kingdom. They can either exist as single cells or make up a multicellular body called a mycelium, which consists of filaments known as hyphea. Most fungi are either parasites or saprophytes (live of dead things) on other organisms.
G
Gene: The basic unit of heredity that transmits information from one generation to another. Genes consist of specific sequences of DNA nucleotides which code for the construction of a particular protein.
Gene cassette: Consists of the functional gene plus its regulatory genes and introns etc.
Gene cloning: The production of exact copies (clones) of a particular gene or genes using genetic engineering techniques. Gene cloning facilitates gene sequencing; it also enables large quantities of a desired protein product to be produced: human insulin, for example, is now produced by bacteria containing the cloned insulin gene.
Gene construct: A sequence of genes made by joining several genes together artificially in the laboratory.
Gene expression: When a gene operates or is switched on in an organism it is said to be expressed.
Gene gun: see biolistics
Gene sequence: The order of the bases pairs (bp) in DNA making up a gene or genes.
Gene splicing: A stage in the processing of messenger RNA, occurring only in eukaryotic cells, in which noncoding introns are removed from the primary mRNA transcript and the coding exons are spliced together to form the functional mRNA molecule.
Gene stacking: When several different traits are genetically engineered into a plant or other organism. For example, some crops are genetically engineered to be tolerant to a herbicide and also to be insect resistant.
Genetic code: The sequence of nucleotide bases pairs (bp) in DNA are read in triplets (codons). Each codon is responsible for the placing of one amino acid in the polypeptide chain during translation. This code appears to be universal across all species from bacteria to mammals.
Genetic engineering: The techniques involved in altering the characters of and organism by inserting genes from another organism into its DNA. This altered DNA (known as recombinant DNA) is usually produced by gene cloning.
Genetic modification: An alternative term for genetic engineering.
Genome: The complete genetic material of a cell.
Genomics: The study of the genome - to establish its sequence and function.
Glufosinate: A broad spectrum, contact herbicide made by AgrEvo (now part of Aventis). Marketed under various trade names including Liberty and Basta. Many crops have been genetically engineered to be resistant to its effect so a farmer can spray a crop with glufosinate, killing the weeds but leaving the crop unharmed. The system is known as 'Liberty Link'.
Gluphosinate: See glufosinate ammonium.
Glyphosate: A broad spectrum, systemically acting (the chemical is taken into the plant and distributed though out it) herbicide made by Monsanto. Marketed under the trade name 'Roundup'. Many crops have been genetically engineered to be resistant to its effect so a farmer can spray a crop with glyphosate, killing the weeds but leaving the crop unharmed. The system is known as 'Roundup Ready'.
H
Herbicide: Any chemical weed killer. Herbicides can be selective, killing only a specific range of plants or they can be broad spectrum herbicides killing a much wider number species.
Herbicide tolerance: When a plant has been genetically engineered to tolerate the effects of a herbicide (weedkiller). A farmer can spray a crop with the herbicide, killing the weeds but leaving the crop unharmed.
Heterozygote: See allele.
Homozygote: See allele.
Host organism: The organism into which the genes are being transferred from the donor organism
Hybrid: A crop line produced by crossing two genetically different parents. The offspring often show 'hybrid vigour' with better yields than either of the parent plants.
I
Insect resistance: When a plant has been genetically engineered to be resistant to insects. Often done by introducing a gene for an insecticidal toxin into the plant such as the toxin gene from Bacillus thuringiensis (Bt toxin) or a lectin gene from the snowdrop.
Insecticide: Any chemical which kills insects. They can be toxic to all insects (e.g. pyrethrum) or a specific group.
Intron: 'Intervening sequence' A nucleotide sequence in a gene that does not code for the gene product. Introns, which are only found in eukaryotes, are transcribed into messenger RNA but are subsequently removed from the transcript before translation. Their functional significance is controversial.
J
K
L
Liberty: See glufosinate ammonium.
M
Marker gene: A marker gene has a characteristic that can be selected for in the laboratory. They are used in genetic engineering to identify when the foreign genes have been successfully integrated into the host organism. Marker genes include antibiotic resistance, genes that cause fluorescence and others that trigger colour changes (e.g. the GUS gene).
Micro-organism: An organism which cannot be seen with the naked eye. These include bacteria, viruses and yeasts.
N
National Seed Listing: Before a seed variety can be sold in the UK it is necessary for it to be placed on the national seed list. This requires the variety going through a series of trials to determine its stability, distinctiveness and uniformity. The theory is that this maintains a high standard of seed from which farmers and other growers can choose from.
Nucleus: The structure or 'organelle' within plant and animal cells which contains the chromosomes
O
P
Patent: A patent is a monopoly right to the commercial exploitation of an invention for a period of 17-20 years. In exchange, the patent holder publishes information about the invention. A patent must fulfil three criteria: novelty (not obvious); inventive (not a discovery) and utility (can be practically used) Since the introduction of genetic engineering, genes, cells and organisms have become patentable.
Pesticide: A general term for fungicides, insecticides and herbicides.
Phenotype: The observable characteristics of an organism such as hair or eye colour in humans and flower colour and size in plants.
Phosphothrinocin: see glufosinate ammonium.
Plasmid: A circular length of DNA found in bacteria that replicates independently of the chromosomes. It plays an important role in gene transfer and in infection. Their relatively simple structure and the ability of some plasmids to transfer DNA into an organisms' genetic material, makes them widely used in genetic engineering.
Polypeptide: See protein
Prokaryote: Any organism belonging to the kingdom Prokaryotae (or Monera), in which the genetic material is not enclosed in a cell nucleus. Bacteria are prokaryotes.
Promoter: The key control element that triggers a gene to operate through the production of mRNA.
Protein: Proteins are complex molecules that are the basic building blocks of cells. Protein molecules consist of one or several long chains of amino acids (polypeptides) linked in a characteristic sequence. These polypeptides undergo coiling and pleating, to create a characteristic shape. Both the amino acid sequence and the final shape of the protein determine the many crucial roles that they play in living organisms.
Q
R
recombinant DNA (r DNA) technology.: Another term for genetic engineering.
Regulator gene / Regulatory sequence: Includes promoter, terminator and other genes that control the expression of a gene. They determine when a gene operates (is switched on or off) and which cells in an organism the gene is expressed.
Restriction enzymes: Enzymes used in the process of genetic engineering that cuts DNA at specific sites - a sort of molecular scissors.
Ribosome: A small spherical body within a living cell which consists of a type of RNA called ribosomal RNA and protein. There are usually many ribosomes in a cell.
RNA: A molecule involved in translating the DNA code into protein synthesis. It is formed of a long chain of four bases - cytosine, guanine, adenine and uracil. Messenger RNA (mRNA) carries the genetic code from the DNA to specialised sites in the cell known as ribosomes. Ribosomal RNA (rRNA) is present in the ribosomes and transfer RNA (tRNA) is involved in the protein assembly process at the ribosomes
Roundup: see glyphosate
S
Selectable marker gene: see marker gene.
Sense gene: Insertion of a gene, by genetic engineering, in the same orientation as a gene found naturally in an organism. It interferes with the normal functioning of a gene. It has been used in systems to delay ripening of fruits.
Streptomyces hygroscopicus: A soil bacterium often used in genetic engineering.
T
T-DNA: 'transferred' DNA - DNA transferred using genetic engineering. T-DNA is part of a plasmid, at one end is the left border at the other the right border.
Terminator: A DNA sequence that switches off the operation of a gene.
Ti-plasmid: A 'tumour-inducing' plasmid with the ability to transfer DNA from the plasmid into the host genome. Ti plasmids are found in Agrobacterium tumifacienes and non-virulent forms are commonly used in plant genetic engineering to transfer genetic material.
Trait: An observable characteristic such as colour, herbicide tolerance etc.
Transformation: The process of actually putting the foreign genes into a new species. Each time this is done it is called a transformation event.
Transcription: The process in living cells in which the genetic information of DNA is transferred to a complementary strand of messenger RNA (mRNA) as the first step in protein synthesis. Transcription takes place in the cell nucleus or nuclear region and the mRNA moves to the protein production site in the ribosome.
Transgene(s): The gene(s) transferred into another organism using genetic engineering.
Transgenic organism: An organism that contains foreign genes created by the use of genetic engineering.
Translation: The process of translating the code in messenger RNA (mRNA) into protein production in the ribosome.
Truncated gene: A gene which has been shortened, that is some of the base pairs (bp) have been removed. Truncated genes may or may not function differently from their full length counterparts depending on which and how many base pairs have been removed.
U
V
Vector: A piece of DNA that can incorporate foreign DNA and transfer it between organisms.
Virus: A organism that is too small to be seen with a light microscope but is capable of independent metabolism and reproduction within a living cell. A mature virus (a virion) ranges in size from 20 - 400 nm in diameter. It consists of core of nucleic acid (DNA or RNA) surrounded by a protein coat (capsid). Some bear an outer envelope (enveloped viruses). Inside its host cell the virus initiates the synthesis of viral proteins and undergoes replication. The new virions are released when the host cell disintegrates. Viruses are parasites of animals, plants, and some bacteria (known as bacteriophages).
W
X
Xeno-transplantation: The use of animal organs for transplantation to humans. Animals are being genetically engineered to look more human to the immune system and thus decrease the likely hood of rejection. There are concerns about the potential for disease causing viruses to be transferred.
Y
Yeast: A group of unicellular cellular fungi of the class Hemiascomycetae and phylum Ascomycota. They occur as single cells or as groups or chains of cells. They reproduce both sexually and asexually. Yeasts of the genus Saccharomyces ferment sugars and are hence used in baking and brewing. Mans ability to and long history of culturing yeasts has made them useful tools in genetic engineering.
Z

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