glossary of terms for marine biotechnology

amino acids
Organic compounds linked together in a linear chain to form proteins. There are 20 amino acids commonly found in proteins.

antigen
A substance (e.g., a virus or bacterium) that causes an immune system response.

antigenic determinant
A molecule (such as a glycoprotein) on the surface of a microbe or macromolecule that triggers an immune response.

antisense RNA (anti-sense RNA)
A complementary RNA sequence that binds to (and thus blocks the transcription of) a naturally occurring (sense) messenger RNA molecule.

antisense strand (anticoding strand)
The strand of DNA which is not used during transcription to make messenger RNA (mRNA). The mRNA made during transcription thus has the same sequence as this strand (so that the eventual protein will be a sense version).

aryl hydrocarbon receptor (AhR),
An intracellular protein that mediates most dioxin effects. This protein has been well studied in mammals, but has not been extensively characterized in non-mammalian vertebrates.

bacteria (sing. bacterium)
Tiny, unicellular, prokaryotic organisms that reproduce by cell division and usually have cell walls; can be shaped like spheres, rods or spirals and can be found in virtually any environment.

base
1. base: Any basic (alkaline) compound containing nitrogen, but generally referring to one of four complex molecules (nucleotides) that form the building blocks of the nucleic acids, DNA and RNA.

2. base (alkali, Bronsted base, Arrhenius base, Lewis base)
A fundamental category of many compounds whose water-based solutions have a bitter taste, a slippery feel in water, turn red litmus paper blue, and can react with acids to form salts. A base has a pH higher than 7; a strong base will have a pH of 13 or higher. Specific types of bases include:
Arrhenius base: any chemical that increases the number of free hydroxide ions (OH-) when they're added to a water-based solution. The more ions produced, the stronger the acid.
Bronsted or Bronsted-Lowry base: any chemical that acts as a proton acceptor in a chemical reaction.
Lewis base: any chemical that donates two electrons to form a covalent bond during a chemical reaction.

benthos
All plants and animals closely associated with the bottom of water, especially in the ocean (benthic)

bio-
Prefix meaning"biologically based," often attached to verbs and nouns in a biotechnology context (e.g., bioprocessing, biomedicine).

bioassay
In chemistry, the determination of the concentration of a chemical by its effect on the growth of an organism under experimental conditions. In toxicology, the use of a live organism or cell culture to test for the presence of a chemical.

A coating or covering on the surface of a living or nonliving substrate composed of organisms like bacteria, protozoa, algae, and invertebrate animals. (For in depth info on biofilms, go to this Sea Grant link.)

biogeography
The study of the distribution of different species of organisms around the planet and the factors that influenced that distribution.

bioinformatics
The use of computers and information technology to analyze and interpret genomic data, such as nucleotide and amino acid sequences and protein structures for the ultimate goal of discovering new biological insights. The tools of bioinformatics include databases, algorithms and statistics, and visualization programs. (For more information, see Bioinformatics Science Primer at the National Center for Biotechnology Information.)

biomarker
Key stress-response proteins used in rapid tests to detect environmental stressors, such as pathogens or pollutants.

biomaterials
Materials with chemical, physical, mechanical, or "intelligent" properties produced through processes that employ or mimic biological phenomena.

biomolecule
Any organic molecule that is an essential part of a living organism.

bioremediation
1. The act of treating waste or pollutants by the use of microorganisms (as bacteria) that can break down the undesirable substances. 2. The branch of biotechnology that uses biological process to overcome environmental problems.

cell
The smallest structural and functional unit of living organisms, generally having a nucleus, cytoplasm, and a surrounding membrane.

cell culture
The propagation in culture of cells removed from a plant or animal.

Cell line
A cell line is generations of cells directly descended from the same cell, each one a microcosm of the whole organism and containing within it genes that dictate the organism's characteristics and behavior.

chloramphenicol acetyl transferase assay (CAT assay)
A lab technique used to determine whether a given fragment of DNA has a promoter on it to encourage transcription to occur, by attaching the gene (called the CAT gene) which codes for the CAT enzyme to it, and observing whether the CAT enzyme is produced.

chromosome
Rod-like structures composed of highly coiled DNA and proteins. Chromosomes are the self-replicating genetic structure of cells. They contain the cellular DNA that bears in its nucleotide sequence the linear array of genes. In prokaryotes, chromosomal DNA is circular, and the entire genome is carried on one chromosome. Eukaryotic genomes consist of a number of chromosomes whose DNA is associated with different kinds of proteins.

cloning
The use of techniques of molecular biology to asexually produce multiple genetically identical copies segments of DNA, usually genes, from a single ancestor.

Cloning vector
A DNA molecule originating from a virus, a plasmid, or the cell of a higher organism into which another DNA fragment of appropriate size can be integrated without loss of the vector's capacity for self-replication. Vectors introduce foreign DNA into host cells, where it can be reproduced in large quantities. Examples are plasmids, cosmids, and yeast. Vectors are often recombinant molecules containing DNA sequences from several sources.

complementary DNA cloning (cDNA cloning)
A lab technique where a double-stranded cDNA (copy DNA) molecule (or dscDNA) is inserted into a cloning vector (another DNA molecule which will continue to be capable of replication after insertion of foreign material), so that the gene encoded by the cDNA can be expressed (transcribed and used) or so many copies of the gene can be made.

complementary DNA library (cDNA library)
A collection of all of the mRNA molecules present in a cell or organism, all turned into complementary or copy (cDNA) molecules with the enzyme reverse transcriptase, then inserted into vectors (other DNA molecules which can continue to replicate after addition of foreign DNA). The library can then be probed for the specific cDNA (and thus mRNA) of interest.

cytometry (flow cytometry)
Analysis of biological material by detection of the light-absorbing or fluorescing properties of cells or subcellular fractions (i.e., chromosomes) passing in a narrow stream through a laser beam. An absorbance or fluorescence profile of the sample is produced. Automated sorting devices, used to fractionate samples, sort successive droplets of the analyzed stream into different fractions depending on the fluorescence emitted by each droplet.

dalton
A unit of mass that equals the weight of a hydrogen atom, or 1.657 x 10-24 grams. Named for John Dalton, an early nineteenth century British chemist who proposed the atomic theory of matter.

dideoxy sequencing (Sanger sequencing)
A lab technique to find out the sequence of nucleotide bases in a DNA molecule, invented by Fred Sanger. The technique involves putting the DNA molecule and the components needed to replicate it into each of four test tubes, along with one of the four types of dideoxynucleotides (ddA, ddT, ddC, ddG), which are molecules that cause the premature termination of replication at the base that they substitute for. The result is that each of the test tubes contains fragments of the DNA molecule that all end at the same base, but at different points on the molecule where the base occurs. The contents of the test tubes are then separated by size with gel electrophoresis (one gel well per test tube; four total wells); the smallest fragments will travel the farthest and the largest will travel the least far from the well. The sequence can then be determined from the picture of the finished gel by noting the sequence of the marks on the gel and from the wells which they came from.

diploid
A full set of genetic material, consisting of paired chromosomes, one chromosome from each parental set. Most animal cells except the gametes have a diploid set of chromosomes. The diploid human genome has 46 chromosomes. Compare haploid.

DNA (deoxyribonucleic acid)
The molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. The four nucleotides in DNA contain the bases: adenine (A), guanine (G), cytosine (C), and thymine (T). In nature, base pairs form only between A and T and between G and C; thus the base sequence of each single strand can be deduced from that of its partner.

DNA annealing
The sticking together (renaturing) of complementary single strands of DNA to make a double-stranded DNA after the strands have first been pulled apart (denatured). This involves the formation of hydrogen bonds between the base pairs.

DNA diagnosis
The use of DNA polymorphisms to detect the presence of a disease gene.

DNA filter assay
A lab technique used to identify the complementary base sequences of DNA. It involves immobilizing the DNA on a filter and putting it in a solution that contains radioactively labeled probe DNA or RNA molecules.

DNA fingerprinting
A lab technique that compares the patterns of bands on analogous DNA fragments from two or more separate individuals; this is done to find out how closely related they are to each another.

DNA helicase
Normally, DNA is in a super-coiled state which makes its genes and other sites difficult to access. This enzyme removes the supercoiling from DNA, or unwinds it, enabling the replication process.

DNA hybridization
This lab technique is used to learn out how closely two or more strands of DNA from different species are related to each other. The technique involves radioactive labeling.

DNA Polymerase I
DNA Polymerase I is an enzyme that aids in DNA replication. It has the following 3 functions:
1) polymerizes in the 5' to 3' direction on single-stranded template;
2) degrades single or double-stranded DNA from a free 3'-OH end; and
3) degrades double-stranded DNA from a free 5'-end.

DNA polymerase II
An enzyme that aids in DNA replication. It has a number of different functions, including the repair of ultraviolet radiation-damaged DNA.

DNA polymerase III
An enzyme that aids in DNA replication. It has a number of different functions, such as:
1) proofreading newly replicated DNA; 2) removing nucleotides from the 3'-end of the strand one by one; and 3) binding nucleotides from the 5'-end of the strand.

DNA polymerization
The making of a DNA molecule from nucleotide monomers by linking them together in a long chain (a polymer).

DNA repair
Any of a number of processes that repair damaged DNA. In general, enzymes remove the damaged portions of the molecule, leaving holes where bases should berth damaged parts could range from a single nitrogenous base to a large number of them; the enzymes doing the removing depend on the specific type of damage) Then other enzymes remove an entire segment of DNA, in the middle of which was the hole or holes. A DNA polymerase I comes and fills the gap with new nitrogenous bases, based on what bases are on the opposite (presumably unharmed) strand of DNA (if both strands are harmed, a process is invoked which inserts bases at random into the strand). Finally a ligase enzyme seals the phosphate backbone back together.

DNA sequencing
Any lab technique used to find out the sequence of nucleotide bases in a DNA molecule or fragment. Examples are dideoxy sequencing and Maxam-Gilbert sequencing.

DNA tumor virus
A virus which uses DNA to code its genome and causes tumors in animals.

DNA unwinding protein
This protein attaches to single-stranded DNA after it has been unwound for replication or recombination and helps it stay unwound.

DNase (deoxyribonuclease, DNAase)
An enzyme which breaks the DNA molecule into smaller pieces.

DNA I, II and III
Refers to circular DNA removed from viruses and as plasmids. Form I is the DNA in its normal, supercoiled form. Form II is the DNA after one of the two strands has been nicked (cut apart), and is circular. Form III is the DNA after both strands have been broken, and is linear.

enzymes
Enzymes are proteins able to accelerate certain organic reactions. The origin of the word 'enzyme' is Greek and means 'within the yeast'. Many enzymes, used in industry or pharmaceuticals are produced by microorganisms (such as bacteria). The organisms are popular because they can produce proteins in large quantities and very often in a short time-scale. The gene encoding for a particular protein can be introduced in the microorganism with the help of DNA techniques. The microorganisms are grown in big production or fermenting vessels in a liquid medium together with the necessary nutrients. Often the protein in question is isolated immediately within the medium.

ELISA (enzyme-linked immunosorbent assay)
A highly sensitive technique for detecting and measuring antigens or antibodies in a solution. The solution is run over a surface to which immobilized antibodies specific to the substance have been attached, and if the substance is present, it will bind to the antibody layer, and its presence is verified and visualized with an application of antibodies that have been tagged in some way.

eukaryote
Cell or organism with membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments. Eukaryotes include all organisms except viruses, bacteria, and bluegreen algae.

expression vector
1) A cloning vector that contains the necessary regulatory sequences to allow transcription and translation of a cloned gene or genes. 2) A cloning vector which is able to replicate and transcribe clone DNA.

fluorescence immunoassay
A sensitive technique which uses fluorescein, a fluorescent molecule, to measure the antigen or antibody concentration in a solution.

focus-forming assay
A lab technique used to find out if a particular piece of DNA contains oncogenes (genes which are associated with cancer). This is done by putting the DNA into animal cells which normally show contact inhibition, or which stop growing when they come into physical contact with other cells or reach a certain density in the culture. If the cells lose contact inhibition and form areas of densely-packed cells (called foci) after receiving the DNA, it means that the DNA did contain oncogenes.

functional genomics
The use of rapid and efficient, or high-throughput methods, to study the functions of many genes at once. These methods include microarrays, which make it possible to screen large numbers of DNA samples simultaneously and economically.

The basic physical and functional units of heredity. Genes are specific sequences of DNA bases that encode instructions on how to make proteins. Each chromosome contains many genes.

gene cloning (DNA cloning)
A lab technique which uses DNA manipulation procedures to produce a recombinant DNA molecule and then to make multiple copies of it by inserting it into the genome of a host microorganism, which is then grown in a culture.

gene expression
The term to describe the transcription of information contained within the DNA into messenger RNA (mRNA) molecules that are then translated into the proteins that perform the critical functions of cells. Gene expression is a highly complex process that allows a cell to respond dynamically to environmental stimuli and to its own changing needs.

gene technology
Technology in the course of which DNA is recombined. When this happens with the DNA of two different organisms, a piece of foreign DNA is introduced or separated in. When a small piece of DNA has been withdrawn from the organism, this is called separating out. Gene technology also is referred to as 'genetic manipulation' or 'recombined DNA technology.'

genetic engineering (gene manipulation, genetic manipulation)
The manipulation of an organism's genetic endowment by introducing or eliminating specific genes through modern molecular biology techniques. A broad definition of genetic engineering also includes selective breeding and other means of artificial selection.

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

genome projects
Research and technology development efforts aimed at mapping and sequencing some or all of the genome of human beings and other organisms.

genomic DNA
The DNA found in an organism's genome which is passed on to offspring as information necessary for survival. The phrase is used to distinguish between other types of DNA, such as found within plasmids.

genomics
The sequencing, annotating, and interpreting of information contained within the genome of an organism.

glycoprotein
A protein linked to a sugar or polysaccharide which are components of receptor molecules on the outer surface of cells.

haploidiploidy
Haploidiploidy is a genetic system in which one sex of the species (usually the male) is haploid (has only one set of chromosomes) and develops from eggs which have not been fertilized by sperm, and the other sex (usually the female) is diploid (has two sets of chromosomes) and develops from fertilized eggs. An example species is the honeybee.

Hepadnaviridae
A family of DNA-containing viruses that infect cause hepatitis in a wide range of vertebrate species.

host-vector system:
A combination of a bacterial host cell (i.e. a specific strain) and a virus vector (i.e. a particular bacteriophage strain) which work well together for DNA cloning.

Human Genome Project
In the 1960s and 1970s, Professor Walter Fiers, University of Gent, became the first to decipher the genome of a complete organism, a virus with about 3,500 little building blocks within its DNA. In 1990, the "Human Genome Project" was started to unravel the complete humane genome, with its more than three billion building blocks. Initially, the scientists involved in this project from laboratories around the world thought they would need at least 15 years to do so. But in 1998 applied techniques moved rapidly. By summer 2000 the complete genetic human 'map' was known. In February 2001, it was published in the magazines Nature and Science. More information can be found on the web: www.ornl.gov/TechResources/Human_Genome/.

hybrid DNA
A double-stranded DNA molecule which was made by hybridizing two single-stranded DNA molecules from two different sources. If the two single-stranded DNA molecules have enough nucleotide sequences in common, they are able to form hydrogen bonds to each other's common sequences.

hybrid molecule:
A double-stranded nucleic acid molecule which was artificially created from two different single-stranded nucleic acid molecules from different sources, for the purpose of comparing their nucleotide sequences.

hydrophilic signaling molecule: A type of molecule which, because it is easily dissolved in water (it is hydrophilic), can easily move through cell membranes and thus can be secreted from one cell and move into a target cell where it triggers a particular event. Many hormones and growth factors are hydrophilic signaling molecules.

hydrothermal vents: The Earth's tectonic plates can move apart, and as they do, the seafloor cracks. Cold seawater seeps deep down into the cracks, becomes super-heated by magma, and then gushes back out into the ocean, forming hydrothermal vents. (Adapted from University of Delaware Extreme 2003 web site)

In vitro
Meaning 'outside the organism.' For example, in vitro-fertilization means that ova are incubated in a Petri dish together with sperm cells.

insertion vector
A cloning vector derived from bacteriophage lambda which has had most of its normal genes removed to make room for new DNA of interest to science, which are then inserted by recombination.

In vitro transcription / in vitro translation
The transcription of a DNA molecule into messenger RNA (mRNA) molecules, and the subsequent translation of the mRNA molecules into polypeptides within a laboratory mixture, containing ribosomes, enzymes, and all of the necessary components (as opposed to transcription and translation within a living cell, where they normally occur).

macromolecule
A molecule with a molecular weight in excess of 1,000 daltons.

marine biotechnology
1) the application of molecular and cellular biology to marine and fresh water organisms for the purpose of identifying, developing, and enhancing products derived from these organisms (definition from U.S. House of Representatives). 2) The application of molecular biological methods to the production or modification of potential commercial products. This includes the use of marine species for the application, or the use of molecular bio-techniques in the marine environment. 3) Marine biotechnology is the manipulation of marine organisms to produce a beneficial product for humankind.

Maxam-Gilbert sequencing
A lab technique used to find out the sequence of nucleotide bases in a nucleic acid (a DNA or RNA molecule). The technique involves putting copies of the nucleic acid into separate test tubes, each of which contains a chemical that will cleave the molecule at a different base (either adenine, guanine, cytosine, thymine, or uracil, the last depending on whether it is DNA or RNA). The result is that each of the test tubes contains fragments of the nucleic acid that all end at the same base, but at different points on the molecule where the base occurs. The contents of the test tubes are then separated by size with gel electrophoresis (one gel well per test tube; four total wells); the smallest fragments will travel the farthest and the largest will travel the least far from the well. The sequence can then be determined from the picture of the finished gel by noting the sequence of the marks on the gel and from which well they came from.

A substance vital to the metabolism of a certain organism, or a product of metabolism.

microarray
Also referred to as a DNA chip. Minute amounts of DNA, RNA, or protein are laid down in a specific pattern on a small piece of glass or fabric. These chips are exposed to fluorescently labeled probes of various sorts and examined with an instrument designed to read the pattern of fluorescence, and to analyze the information the pattern provides. For example, some probes cause the genes that were active in cells at the time their DNA was harvested to light up in different in different colors. Because the microarrays make it possible to screen large numbers of DNA samples simultaneously and economically, they are considered a high throughput technology.

nitrogenous base
A nitrogen-containing molecule having the chemical properties of a base.

nucleotide
A subunit of DNA or RNA consisting of a nitrogenous base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule, and a sugar molecule (deoxyribose in DNA and ribose in RNA). Thousands of nucleotides are linked to form a DNA or RNA molecule.

In medicine pathways indicates a sequence of biochemical reactions involved in a metabolic process.

PCR-technique
See Polymerase Chain Reaction. This technique to copy DNA was invented in 1980 by scientist Carry Mullis and signaled a revolution in the world of biotechnology.

plasmid
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. A number of artificially constructed plasmids are used as cloning vectors.

polymerase, DNA or RNA
Enzymes that catalyze the synthesis of nucleic acids on preexisting nucleic acid templates, assembling RNA from ribonucleotides or DNA from deoxyribonucleotides.

polymerase chain reaction
A method for amplifying a DNA base sequence using a heat-stable polymerase and two 20-base primers, one complementary to the (+) strand at one end of the sequence to be amplified and one complementary to the (-) strand at the other end. Because the newly synthesized DNA strands can subsequently serve as additional templates for the same primer sequences, successive rounds of primer annealing, strand elongation, and dissociation produce rapid and highly specific amplification of the desired sequence. PCR also can be used to detect the existence of the defined sequence in a DNA sample. (Definition from dictionary, Human Genome Information Web Site.)

polyploid (polyploidy)
Having more than the normal (diploid) number of chromosomes; a multiple of the haploid number that is caused by the chromosomal replication without nuclear division.

probe
1) Gene Probe: A biomolecule that is labeled with radioactive isotopes or with a fluorescent marker that selectively binds to a specific gene so it can be isolated or identified.
2) hybridization probe: A single-stranded nucleic acid molecule with a known nucleotide sequence which is labeled in some way (for example, radioactively, fluorescently, immunologically) and used to find and mark certain DNA or RNA sequences of interest to a researcher by hybridizing to it.

prokaryote
Cell or organism lacking a membrane-bound, structurally discrete nucleus and other subcellular compartments. Bacteria are examples of prokaryotes.

proteins
Proteins are large, complex molecules made ups of smaller subunits called amino acids The cells give instructions to create proteins. Each protein has a particular function, necessary for survival, growth, division and functioning of the cell. Insulin, for example, is a protein allowing a person to assimilate sugars. An error within one of the genes can bring about a modification in the insulin level and cause diabetes. If we look upon DNA as the instruction book of biological life, proteins would be the 'performers.'

RNA
Ribonucleic acid. This acid is used by the cell as an intermediary in order to transcribe the DNA code into a protein.

receptor
A site on a cell (often on a membrane) that can combine with a specific type of molecule to alter the cell's function. For example, insulin receptors are areas on the outer part of a cell that allow the cell to join or bind with insulin in the blood. When the cell and insulin bind together, the cell can take glucose (sugar) from the blood and use it for energy.

recombinant DNA
A combination of DNA molecules of different origin that are joined using recombinant DNA technologies. 2) Recombinant DNA is a fragment of DNA artificially incorporated into the DNA molecule of a suitable vector so that it can be expressed many times. In this way a large quantity of the DNA in question can be obtained. The DNA is usually one that contains genes of interest, such as interferon, insulin, or growth hormone. The DNA may also be intended to fix mutated genes causing diseases, such as hemophilia or sickle cell anemia. The vector could be plasmids, bacteriophages, and cosmids (packaged plasmid DNA into a phage particle).

recombinant DNA technologies
Procedures used to join together DNA segments in a cell-free system (an environment outside a cell or organism). Under appropriate conditions, a recombinant DNA molecule can enter a cell and replicate there, either autonomously or after it has become integrated into a cellular chromosome.

replacement vector
A cloning vector, such as bacteriophage, in which some of the DNA of the vector can be replaced with foreign DNA. (See vector.)

shuttle vector
A recombinant DNA vector that can be replicated into several different host species. (See vector.)

secretion vector
A DNA vector in which the protein product is both expressed and secreted (excreted) from the cell. (See vector.)

stem cells
Undifferentiated, primitive cells in the bone marrow that have the ability both to multiply and to differentiate into specific blood cells. Stem cells could be described as "basic or primal cells," containing all genetic information, which have not yet differentiated into cells with specific functions, e.g., muscle cells, liver cells, or neurons. Several kinds of cells are well-known, including embryonic stem cells and full-grown stem cells.

structural biology
The study of the 3-dimensional structures of biological macromolecules and the effort to determine the function of these molecules from their structure.

symbiosis
A type of organism-organism interaction where one organism lives in intimate association with another. Types of symbiotic relationships are mutualism, commensalism, and parasitism.

transcription
The synthesis of an RNA copy from a sequence of DNA (a gene); the first step in gene expression. Compare translation.
1. posttranscriptional processing: The enzymatic processing of the primary RNA transcript, which produces messenger RNA and transfer RNA.
2. reverse transcription: The process of copying information found in RNA into DNA.

transgenic
This term describes an organism that has had genes from another organism put into its genome through recombinant DNA techniques.

transgenic animal or plant
Genetically engineered animal or plant or offsprings of genetically engineered animals and plants. The transgenic animal usually contains material from at lease one unrelated organism, such as from a virus, plant, or other animal. The transgenic organism is formed by the insertion of foreign genetic material into a germ cell.

vaccine
The terms vaccine and vaccination are derived from the word "vacca", the Latin word for 'cow.' It was used for the first time by Edward Jenner in 1796, who discovered that an infection with cowpox could protect someone completely and permanently against smallpox.

vector
1) A DNA molecule that replicates on its own in a host cell and can be used as a vehicle in the laboratory for replicating other types of DNA. A vector could be plasmids, bacteriophages, and cosmids (packaged plasmid DNA into a phage particle). 2) An organism that spreads an infectious disease; often, this infectious host is not affected by the illness.

viral vector
Viral DNA that has been modified to serve as a vector for recombinant DNA. (See vector).

virus
A noncellular biological entity that can reproduce only within a host cell. Viruses consist of nucleic acid covered by protein. Some animal viruses also are surrounded by membrane. Inside the infected cell, the virus uses the synthetic capability of the host to produce progeny virus.

yeast vectors
Yeast cells that contain plasmids carrying newly-introduced genes.