Soil bacteria that often possesses the Ri plasmid, and might cause the hairy root symptom in plants. It is used in plant transformation.

Soil bacteria that often possesses the Ti plasmid, and might cause the crown gall tumor in plants. It is used in plant transformation.

One of a number of different forms of a gene. Each person inherits two alleles for each gene, one from each parent. These alleles might be the same or might be different from one another.

One of 20 different molecules that combine to form proteins. The sequence of amino acids in a protein determines the protein structure and function.

The triplet of nucleotides in transfer RNA, which associates by complementary base pairing with a specific triplet (codon) in messenger RNA during protein synthesis.

Gene in the reverse orientation in relation to the promoter, which when transcribed, produces a complementary polynucleotide to the gene in the original orientation.

The process that, when functioning normally, programs cells to self-destruct at an appropriate moment in an organism's life cycle. If the apoptotic process malfunctions in a cell, uncontrolled cell growth can result, which can contribute to the development of cancer. Such disruption of apoptosis might be associated with an inherited genetic mutation or a somatic cell genetic mutation.

A vector used to clone DNA fragments of 100 to 300 kb insert size (average of 150 kb) in Escherichia coli cells. Based on the naturally occurring F-factor plasmid found in the bacterium Escherichia coli.

An insecticidal soil bacterium, marketed worldwide for control of many important plant pests, mainly caterpillars of the genus Lepidoptera (butterflies and moths), but also for control of mosquito larvae. The toxin genes from Bt have also been genetically engineered into several crop plants.

One of the molecules (adenine, guanine, cytosine, thymine, or uracil) that form part of the structure of DNA and RNA molecules. The order of bases in a DNA molecule determines the structure of proteins encoded by that DNA.

See Also Nucleotide.

Two complementary nucleotide bases joined together by chemical bonds. The two strands of the DNA molecule are held together in the shape of a double helix by the bonds between base pairs. The base adenine pairs with thymine, and guanine pairs with cytosine.

The process whereby a compound is decomposed by natural biological activity. A biodegradable substance is one in which a microbe can reduce it to CO₂ and H₂O by mineralization.

All living organisms in an ecosystem.

The science of informatics as applied to biological research. Informatics is the management and analysis of data using advanced computing techniques. Bioinformatics is particularly important as an adjunct to genomics research because of the large amount of complex data this research generates.

A method (biological ballistics) of transforming cells by bombarding them with microprojectiles coated with DNA.

Individuals used for production of biotech products such as proteins, enzymes, and so on.

The use of biological agents to render hazardous wastes nonhazardous or less hazardous.

Science that deals with the evaluation, control, and minimization of risks from biotechnology. Biosafety is concerned with risks to human and animal health and to the environment.

The application of biological research techniques to the development of products or processes, using biological systems, living organisms, or derivatives thereof. It can also be understood as a range of different molecular technologies such as gene manipulation and gene transfer, DNA typing, and cloning of microorganisms, plants, and animals.

See Base pair (bp).

Genes that normally help to restrain cell growth, but can contain certain genetic mutations associated with the development of breast and ovarian cancer. Note, however, that inherited BRCA1 and BRCA2 mutations are thought to account for less than 10 percent of all breast and ovarian cancers. Recent evidence suggests that somatic cell genetic mutations (i.e., noninherited genetic mutations) in these two genes could also play a role in the development of cancer.

Bovine growth hormone. BST is similar to human growth hormone and it is used for improving milk production in cows.

Bacillus thuringiensis. Bt varieties, developed through biotechnology, are carriers of genes for cry or Bt protein, which are lethal to many insects like the European corn borer and others, but are not harmful to mammals.

DNA that is synthesized in the lab from mRNA templates.

Geographic region that has the highest genetic diversity of a species. Sometimes also called center of origin.

The original postulate that genetic information can be transferred only from nucleic acid to nucleic acid and from nucleic acid to protein; that is, from DNA to DNA, from DNA to RNA, and from RNA to protein (although information transfer from RNA to DNA was not excluded and is now known to occur; this is reverse transcription). Transfer of genetic information from protein to nucleic acid never occurs.

One of the serially aligned beads or granules of a eukaryotic chromosome, resulting from local coiling of a continuous DNA thread.

A term applied to genes, cells, or entire organisms that are derived from, and are genetically identical to, a single common ancestor gene, cell, or organism, respectively. Cloning of genes and cells to create many copies in the laboratory is a common procedure essential for biomedical research. Several processes, which are commonly described as cell cloning, give rise to cells, which are almost but not completely genetically identical to the ancestor cell. Cloning of organisms from embryonic cells occurs naturally in nature (e.g., with the occurrence of identical twins). The laboratory cloning of a sheep using the genetic material from a cell of an adult animal has recently been reported. This is the production of an animal with nuclear DNA identical to another animal. Cloning takes place without the contribution of DNA from a male and female, and is therefore “asexual” reproduction.

The process of producing a genetically identical copy.

A set of three nucleotide bases in a DNA or RNA sequence, which together code for a unique amino acid. For example, the set AUG (adenine, uracil, guanine) codes for the amino acid methionine.

Plasmid having a promoter, the coding sequence, and a terminator, that is introduced in a host via biolistic, Agrobacterium, microinjection, and so on, to transform it.

Groups of cloned DNA sequences representing overlapping regions of a genome.

An artificially constructed cloning vector/plasmid that contains cos sites at each end. Cos sites are recognized during head filling of lambda phages. Cosmids are useful for cloning large segments of foreign DNA.

Synthetic RNA produced by transcription from a specific DNA single-stranded template.

The process by which a primitive cell commits to becoming a specialized cell in the body, such as a skin cell or a bone cell.

The molecule that encodes genetic information. DNA is a double-stranded helix held together by bonds between pairs of nucleotides.

An enzyme that closes nicks or discontinuities in one strand of double-stranded DNA by creating an ester bond between adjacent 3' OH and 5' PO₄ ends on the same strand.

An enzyme that can synthesize new DNA strands using a DNA template; several such enzymes exist. There are several classes of enzymes that polymerize DNA nucleotides using single- or double-stranded DNA as a template.

Product with naked DNA used to induce an immune response against the pathogen from which the DNA was obtained.

An allele that determines phenotype even when heterozygous. Also the trait controlled by that allele.

Technique that uses an electric discharge to produce pores on the cell membrane for intake of recombinant DNA.

The combination of all the conditions external to the genome that potentially affect its expression and its structure.

A protein that facilitates a biochemical reaction in a cell. In general, these biochemical reactions would not occur if the enzyme were not present. For example, an enzyme can facilitate (also called catalyze) the destruction of another protein by breaking the bonds between amino acids. An enzyme of that type is called a protease.

A common bacterium that has been studied intensively by geneticists because of its small genome size, normal lack of pathogenicity, and ease of growth in the laboratory.

Multicellular and unicellular organisms (yeast, plants, animals, etc.), with cells that have a distinct nucleus, enveloped by a nuclear membrane.

Controlled human breeding based on notions of desirable and undesirable genotypes.

In Darwinian terms, a gradual change in phenotypic frequencies in a population that results in individuals with improved reproductive success.

A length of DNA, which codes for a particular protein or, in certain cases, a functional or structural RNA molecule.

A group of genes or cloned DNA fragments, which are coordinately controlled.

Isolating a gene and making many copies of it, which is accomplished by inserting the gene's DNA sequence into a vector, transmitting the transgenic construct into a cell, and then allowing the cell to reproduce, thereby creating many identical copies of the gene.

See Gene flow.

The exchange of genetic information among individuals, populations, or species, with the preservation of that genetic information in the following generations.

Idea that every trait is determined by genes (i.e., stature, eye color, tendency to crime, etc.).

Gene usually inserted in the construct to facilitate the visual identification of transformed tissue. Examples are genes for glucaronidase (GUS), luciferase, or green fluorescent protein (GFP).

Partial or total suppression of gene expression.

The correction of a genetic deficiency in a cell, tissue, or organ by the addition of a normal, functioning copy of a gene and its insertion into the genome. This technique should be clearly distinguished from the use of genomics to discover new targets for drug discovery and new diagnostic tools.

The set of codons in DNA or mRNA. Each codon is made up of three nucleotides, which call for a unique amino acid. For example, the set AUG (adenine, uracil, guanine) calls for the amino acid methionine. The sequence of codons along an mRNA molecule specifies the sequence of amino acids in a particular protein.

Altering the genetic material of cells or organisms to make them capable of making new substances or performing new functions.

Loss of genetic diversity and variability caused by either natural or man-made processes.

A map of a genome that shows the relative positions of the genes and/or markers on the chromosomes.

Uncontrolled escape of genetic information (frequently referring to products of genetic engineering) into the genomes of organisms in the environment where those genes never existed before.

Condition of low genetic diversity that might predispose an organism to susceptibility to pests.

All the genetic material in the chromosomes of a particular organism; its size is generally given as its total number of base pairs.

The science of identifying the sequence of DNA in various species, and subsequent processing of that information, or the study of all genes and their function. Recent advances in genomics are bringing about a revolution in our understanding of the molecular mechanisms of disease, including the complex interplay of genetic and environmental factors. Genomics is also stimulating the discovery of breakthrough health products by revealing thousands of new biological targets for the development of drugs and by giving scientists innovative ways to design new drugs, vaccines, and DNA diagnostics. Genomics-based therapeutics include “traditional” small chemical drugs, protein drugs, and potentially gene therapy.

Sperm and egg cells, and their precursors. Germ cells are haploid and have only one set of chromosomes (23 in humans), whereas all other cells have two copies (46 in humans).

All the genetic background of a species.

Genetically modified organism. Loosely defined, it is an organism that has been changed from its natural state. Some define a GMO as an organism in which foreign DNA has been inserted using recombinant DNA technology.

Genetically modified rice variety developed by Ingo Potrykus and Peter Beyer at the Swiss Federal Institute of Technology and University of Freiburg, Germany. Golden Rice has a high content of β-carotene (a vitamin A precursor).

Gene from Escherichia coli used as reporter in transformation.

Product used to kill plants.

This term is used by geneticists in two different senses: one member of a chromosome pair in diploid organisms, or a gene from one species (e.g., the mouse) that has a common origin and functions the same as a gene from another species (e.g., humans, Drosophila, or yeast).

Pertaining to a biochemical process or reaction taking place in a test tube (or more broadly, in a lab) as opposed to taking place in a living cell or organism.

Pertaining to a biological process or reaction taking place in a living cell or organism.

Exotic DNA fragment introduced into a vector.

Protein naturally produced by human body cells that increases the resistance to virus infection. Alpha-interferon is known to be effective against some cancers.

A length of DNA equal to 1,000 nucleotides.

A sequence of bases at a unique physical location in the genome, which varies sufficiently between individuals that its pattern of inheritance can be tracked through families and it can be used to distinguish among cell types. A marker might or might not be part of a gene. Markers are essential for use in linkage studies and genetic maps to help scientists narrow down the possible location of new genes and discover the associations between genetic mutations and disease.

Glass slide with a large number of DNA fragments used for probing biological samples for different attributes and effects.

A change, deletion, or rearrangement in the DNA sequence that could lead to the synthesis of an altered inactive protein or the loss of the ability to produce the protein. If a mutation occurs in a germ cell, then it is a heritable change and can be transmitted from generation to generation. Mutations can also be in somatic cells and are not heritable in the traditional sense of the word, but are transmitted to all daughter cells.

A general term for the process of cloning where the genetic information from a somatic cell is transferred to an egg cell from which the DNA is removed.

One of the family of molecules that includes the DNA and RNA molecules. Nucleic acids were so named because they were originally discovered within the nucleus of cells, but they have since been found to exist outside the nucleus as well.

The building block of nucleic acids, such as the DNA molecule. A nucleotide consists of one of four bases (adenine, guanine, cytosine, or thymine) attached to a phosphate-sugar group. In DNA the sugar group is deoxyribose, whereas in RNA (a DNA-related molecule that helps to translate genetic information into proteins), the sugar group is ribose, and the base uracil substitutes for thymine. Each group of three nucleotides in a gene is known as a codon. A nucleic acid is a long chain of nucleotides joined together, and therefore is sometimes referred to as a polynucleotide.

A gene that is associated with the development of cancer.

A grant issued by the government that gives the patent holder the right to exclude others from making, using, or selling a patented invention for a certain term. In most countries, including the United States, the term begins on the date on which the patent is issued and ends 20 years from the date on which the application for the patent was filed. In the United States, patents are granted on inventions that meet the requirements of novelty, nonobviousness, and utility. A patent holder cannot use a patented invention dominated by the patent of another, absent a license or cross-license.

A powerful method for amplifying specific DNA segments that exploits certain features of DNA replication. For instance, replication requires a primer and specificity is determined by the sequence and size of the primer. The method amplifies specific DNA segments by cycles of template denaturation, primer addition, primer annealing, and replication using a thermostable DNA polymerase. The degree of amplification achieved is set at a theoretical maximum of 2ⁿ, where n is the number of cycles (e.g., 20 cycles gives a theoretical 1,048,576-fold amplification).

Science that studies the correlation between the genome of an individual and his or her response to drugs used in treatments.

Autonomously replicating, extrachromosomal circular DNA molecules, distinct from the normal bacterial genome and nonessential for cell survival under nonselective conditions. Some plasmids are capable of integrating into the host genome and are used as a cloning vector for small pieces of DNA.

Short pre-existing polynucleotide chain to which DNA polymerase can add new deoxyribonucleotides.

Proteinaceous molecules found in the cerebral cell membrane of vertebrate animals. Mutated forms of those molecules might cause neural degenerative diseases, such as mad cow disease.

A segment of DNA located at the “front” end of a gene, which provides a site where the enzymes involved in the transcription process can bind to a DNA molecule and initiate transcription. Promoters are critically involved in the regulation of gene expression.

A biological molecule that consists of many amino acids linked together by peptide bonds. The sequence of amino acids in a protein is determined by the sequence of nucleotides in a DNA molecule. As the chain of amino acids is being synthesized, it is also folded into higher order structure shapes (e.g., helices or flat sheets). Proteins are required for the structure, function, and regulation of cells, tissues, and organs in the body.

The science of identifying the sequence, function, structure, and interrelationship of all proteins in an organism and subsequent processing of that information.

DNA molecules that have been created by combining DNA from more than one source.

The creation and transplantation of healthy cells, tissues, and organs to replace or repair a patient's own damaged or diseased cells, tissues, and organs.

A protein that recognizes specific, short nucleotide sequences and cuts DNA at those sites. Bacteria contain more than 400 such enzymes that recognize and cut over 100 different DNA sequences.

A molecule similar to DNA, which helps in the process of decoding the genetic information carried by DNA.

Determining the order of nucleotides in a DNA or RNA molecule or determining the order of amino acids in a protein.

Any cell in the body except gametes and their precursors. In diploid individuals, somatic cells possess 2n chromosomes.

Undifferentiated, primitive cells in the bone marrow with the ability to both multiply and differentiate into specific blood cells.

The site on a DNA sequence at which transcription stops.

Term used for in vitro growth of cells, tissue, or organs, in aseptic conditions and in a nutritive media.

Cells that have the ability to develop into any of the many different cell types that make up multicellular organisms. Embryos are composed of large numbers of totipotent cells, which decline in number as development proceeds and cell specialization begins to occur. Adults have a much more limited ability to produce totipotent cells than do embryos. Organisms such as humans retain a complete set of genetic information in all adult body cells, but only a small fraction of an adult's cells have the ability to develop into multiple cell types. Recent research has shown that differentiated adult cells can be treated such that they become totipotent. Such totipotent or stem cells offer possibilities for a number of therapeutic uses, such as repairing heart muscle after a heart attack or brain function after a stroke. Plant cells tend to retain a greater capability for totipotence, even in mature plants, than do those of animals.

The process during which the information in a sequence of DNA is used to construct an mRNA molecule.

A process by which the genetic material carried by an individual cell is altered by incorporation of exogenous DNA into its genome.

An organism with a genome that has been altered by the inclusion of foreign genetic material. This foreign genetic material can be derived from other individuals of the same species or from wholly different species. Genetic material can also be artificial. Foreign genetic information can be added to the organism during its early development and incorporated in cells of the entire organism. For example, mice embryos given the gene for rat growth hormone develop into larger adults. Genetic information can also be added later in development to selected portions of the organism. As an example, experimental genetic therapy to treat cystic fibrosis involves selective addition of genes responsible for lung function and is administered directly to the lung tissue of children and adults. Transgenic organisms have been produced that provide enhanced agricultural and pharmaceutical products. Insect-resistant crops and cows that produce human hormones in their milk are but two examples.

The process during which the information in mRNA molecules is used to construct proteins.

An organism that serves to transfer a disease-causing organism (patho-gen) from one organism to another. It is also a mechanism whereby a foreign gene is moved into an organism and inserted into that organism's genome. Retroviruses such as HIV serve as vectors by inserting genetic information (DNA) into the genome of human cells. Bacteria can serve as vectors in plant populations.

A piece of nucleic acid covered by protein. Viruses can only reproduce by infecting a cell and using the host's cellular mechanisms for self-replication, and can cause disease. Modified viruses can also be used as a tool in gene therapy to introduce new DNA into a cell's genome.

Transplantation of tissue or organs between organisms of different species, genus, or family. A common example is the use of pig heart valves in humans.

A vector used to clone DNA fragments (up to 400 kb); it is constructed from the telomeric, centromeric, and replication origin sequences needed for replication in yeast cells. Compare cosmid.

Fungus from the Saccharomycetaceae family, which is used in fermentation of liquor and in bread making.

A cell produced by the fusion of a female gamete (egg cell or ovum) with a male gamete (sperm cell or pollen grain). The joining of a sperm and egg cell is called fertilization. Zygotes are diploid and undergo cell division to become an embryo.