Appendix A. Glossary

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

Abortion

The spontaneous or deliberate termination of pregnancy before the embryo or fetus has been born, or is viable outside the womb.

AID

Artificial insemination using donor sperm (see also artificial insemination).

AIDS

Acquired immunodeficiency syndrome

Alleles

Alternative forms of a genetic locus; alleles are inherited separately from each parent (e.g., at a locus for eye color there might be alleles resulting in blue or brown eyes).

Amino acid:

Any of a group of 20 molecules that combine to form proteins in living things. Chemically they contain an amino group, -NH2, and a carboxyl group, -COOH. The sequence of amino acids in a protein is determined by the genetic code.

Amniocentesis

Diagnostic sampling of the amniotic fluid during pregnancy, usually performed by insertion of a needle into the amniotic fluid which surrounds the fetus during pregnancy. Performed for prenatal screening.

Anencephalic

Literally, the condition of having no encephalon or brain (normally applied to fetuses or infants with no cerebrum).

Anesthesia

The partial or complete loss of sensation with or without consciousness as the result of injury, disease or administration of an anesthetic.

Animal

A living being with a capacity for spontaneous movement and a rapid motor response to stimulation. Animals can be divided into two groups, invertebrates (animals with no backbones) and vertebrates (animals with backbones).

Antibiotic

A substance derived from a fungus or bacterium that inhibits the growth of other microorganisms.

Antibody

A blood protein (immunoglobin) produced by white blood cells in response to the presence of a specific foreign substance (antigen) in the body, with which it fights or otherwise interacts. Antibodies to sperm, if present, can impair fertility by causing agglutination of sperm.

Antisense RNA

RNA that is complementary to the nucleotide sequence of normal mRNA. It therefore forms a duplex with the mRNA preventing the mRNA from being used in protein synthesis, thus indirectly controlling gene expression.

Artificial Insemination

The introduction of sperm into a woman's vagina or uterus by noncoital methods, for the purpose of conception (see AID).

Asexual reproduction

Reproduction of organisms by purely vegetative means without the function and interaction of the two sexes. Examples of asexually reproduced plants are roses, peach trees and lilies.

Autonomy

The governing of one's self according to one's own system of morals and beliefs.

Autoradiography

A technique that uses x-ray film to visualize radioactively labeled molecules or fragments of molecules. For example, it is used in analyzing the length and number of DNA fragments separated by electrophoresis.

Autosome

A chromosome not involved in sex determination. The diploid human genome consists of 46 chromosomes, 22 pairs of autosomes and 1 pair of sex chromosomes.

Bacteria

Single-celled, prokaryotic organisms that reproduce by binary fission.

Bacteriophage

A virus that infects bacteria; also called phage.

Baculovirus

A virus whose host is an insert cell.

Base pair

Two nucleotides (adenosine and thymidine, or guanosine and cytidine) held together by the bonds between individual bases.

Beneficence

The state of doing or producing good; compare to nonmaleficence.

Biopsy

The surgical removal of a cell or sample of tissue for diagnostic purposes.

Biotechnology

The use or development of techniques using organisms (or parts of plants, animals or humans) to provide or improve goods; services to improve the environment.

Birth control

The prevention of birth.

Blastocyst

A hollow ball of cells, filled with fluid, that forms about four days after fertilization from the zygote, and before the beginning of the process of implantation. The embryo develops from a small cluster of cells in the center of the sphere, and the outer wall of the sphere becomes the placenta.

Blastomeres

The daughter cells that derive from the first and subsequent cleavages of the zygote.

Cesarean section

The surgical removal of a fetus through an incision in the pregnant woman's abdominal tissue and uterine wall.

Carcinogen

A substance that causes or increases the risks of getting cancer.

Carrier

Someone who may transmit a genetic condition but who normally does not show any evidence of the disease.

Cell

The smallest component of life. A membrane-bound protoplasmic body that is capable of carrying on all essential life processes. A single cell unit is a complex collection of molecules with many different activities, all integrated to form a functioning, self-assembling, self-regulating and self-reproducing biological unit.

Cell culture

The propagation of cells removed from multicellular organisms in a laboratory environment that has strict sterility, temperature and nutrient requirements.

Cell fusion

The joining of the membrane of two cells, thus creating a single hybrid cell that contains nuclear matter from both the parent cells.

Centimorgan

A unit of measure of genetic recombination frequency. One centimorgan is equal to a 1 percent chance that a genetic locus will be separated from a marker due to recombination in a single generation. In humans, 1 centimorgan is equivalent, on average, to 1 million base pairs.

Centromere

The small junction area between the two arms of a chromosome.

Chimera

An organism formed by the aggregation of cells taken from different genotypes. Chimeric embryos may occur naturally or artificially. An inter-species chimera is formed when the cells are from different species.

Chloroplast

Those structures within plant cells where photosynthesis occurs. They contain small circular DNA molecules that replicate independently of the nucleus.

Chorionic villi

Finger-like projections growing from the external surface of the chorion that contribute to the formation of the placenta.

Chorionic villi sampling (CVS)

The procedure used in prenatal diagnosis to take a small sample of the chorionic villi for testing, such as genetic screening.

Chromosomal abnormalities

Genetic mutations involving changes in the number and structure of chromosomes.

Chromosome

A structure that lies inside a cell's nucleus. A chromosome is composed mainly of DNA. Each normal cell of the human body has 23 pairs of chromosomes.

Cleavage

The stage of a cell division that takes place immediately after fertilization and that lasts until the cells begin to segregate and differentiate and to develop into a blastocyst.

Clones

A collection of cells or organisms that are genetically identical.

Cloning

The process of asexually producing a group of cells (clones), all genetically identical to the original ancestor. In recombinant DNA manipulation, procedures can be used to produce multiple copies of a single gene or segment of DNA.

Codon

A sequence of three DNA base pairs, which codes for an amino acid.

Complementary DNA (cDNA)

DNA that is synthesized from a messenger RNA template; the single-strand form often is used as a probe in physical chromosomal mapping.

Conception

The fertilization of the egg by a sperm that initiates the formation of a zygote (also has been used for implantation).

Conceptus

This term refers to the products of fertilization. It includes the embryo proper, as well as extra embryonic structures and tissues that develop from the zygote (e.g., placenta). It also is called the pre-embryo.

Confidentiality

A fundamental component of the physician-patient relationship, stemming primarily from the Hippocratic oath, in which the physician has the duty to keep confidential all that is confided by the patient.

Conjugation

The reproductive process by which DNA is transferred between bacteria during cell-to-cell contact.

Consanguinity

Descent from common ancestors.

Consequentialism

The normative theory that the rightness or wrongness of actions is determined by anticipated or known consequences; compare to deontologism.

Contigs

Groups of clones representing overlapping, or contiguous regions of a genome.

Copyright

Copyright protection applies to eight categories of works: literary; musical; dramatic; pantomime and choreographic; pictorial, graphic and sculptural; motion pictures and audio-visual work; sound recording; and computer programs. Copyright protects the expression of an idea, not the idea itself.

Covenant

A solemn agreement between two or more parties.

Crossing over

The breaking during meiosis of one maternal and one paternal chromosome, the exchanging of corresponding section of DNA and the rejoining of the chromosomes.

Cryopreservation

The preservation of sperm, embryos and ocytes by freezing them at extremely low temperatures.

Cultivar

An international term denoting certain cultivated plants that are clearly distinguishable from others by one or more characteristics and that when reproduced retain those characteristics. In the United States "variety" is considered to be synonymous with cultivar (derived from cultivated variety).

C-value paradox

The lack of correlation between the amount of DNA in a haploid genome and the biological complexity of the organism. (C-value refers to haploid genome size.)

Cystic fibrosis

A disease that affects the sweat and mucus-secreting glands, resulting in chronic lung disease, pancreatic insufficiency, abnormally salty sweat and in some cases, liver disease.

Cytoplasm(ic)

The substance within a cell external to the nuclear membrane; pertaining to or contained in the cytoplasm.

Deletion

Loss of part of a chromosome.

Deontologism

A theory according to which actions are judged right or wrong based upon inherent right-making characteristics or principles rather than on their consequences.

Determinism

The theory that for every action taken there is causal mechanisms such that no other action is possible.

Diploid

A full set of genetic material (two paired sets of chromosomes), one from each parental set. All cells except sperm and egg cells have a diploid set of chromosomes. The diploid human genome has 46 chromosomes (see 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. There are four nucleotides in DNA: adenosin (A), guanosine (G), cytidine (E) and thymidine (T). In nature, base pairs form only between A and T and between G and C, thus the sequence of each single strand can be deduced from that of its partner.

DNA probes

Segments of single-strand DNA that are labeled with a radioactive or other chemical marker and used to identify complementary sequences of DNA by hybridizing with them (see hybridization).

DNA sequence

The relative order of base pairs, whether in a stretch of DNA, a gene, a chromosome or an entire genome.

Domain

A discrete portion of a protein with its own function. The combination of domains in a single protein determines its unique overall function.

Dominant

A trait or condition that is expressed in individuals who have a single version of a particular gene.

Donor gametes

Eggs or sperm donated by individuals for medically assisted conception.

Double effect, the doctrine of

The theory that an evil effect is morally acceptable provided a proportional good effect will accrue, the evil is not intended, the evil effect is not the means to the good, and the action is not intrinsically evil.

Double helix

The shape assumed when two linear strands of DNA are bonded together.

Ectopic pregnancy

A pregnancy that occurs outside the uterus, usually in a fallopian tube.

Egalitarian

A social philosophy that advocates human equality.

Electrophoresis

A method of separating large molecules (such as DNA fragments or proteins) from a mixture of similar molecules. An electric current is passed through a medium containing the mixture and each kind of molecule travels through the medium at a different rate, depending on its electrical charge and size. Separation is based on these differences.

Embryo

Early or preimplantation embryo refers to the first two weeks after the formation of the zygote. Embryo technically refers to the stage from the third to eighth week of development. Often, the term embryo also encompasses development from the beginning up to the eighth week.

Embryo donation

The transfer from one woman to another of any embryo obtained by artificial insemination and lavage or, more commonly, by IVF.

Embryo lavage

A flushing of the uterus to recover a preimplantation embryo.

Embryo transfer

The transfer of an in vitro fertilized egg from its laboratory dish into the uterus of a woman.

Endogenous

Developing or originating within the organism, or arising from causes within the organism.

Endotoxin

Poison produced by some gram-negative bacteria, present in the cellular membrane, and released only upon cell rupture; composed of complex lipopolysaccharide (fat-like molecule and sugar molecule) and more heat-stable than protein exotoxins.

Enzyme

A protein that acts as a catalyst, speeding the rate at which a biochemical reaction proceeds by not altering its direction or nature.

EPA

U. S. Environmental Protection Agency.

Episome

A DNA molecule that may exist either as integrated parts of a chromosomal DNA molecule of the host or as an independently replicating DNA molecule (plasmid) free of the host chromosome.

Ethics

A system of moral principles or standards that governs conduct.

Eukaryote

A cell or organism with membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments. Eucaryotes include all organisms except viruses, bacteria and blue-green algae. Compare prokaryote.

Eugenics

Attempts to improve hereditary qualities through selective breeding. See positive eugenics, negative eugenics, eugenics of normalcy.

Eugenics of normalcy

Policies and programs that are intended to ensure that each individual has at least a minimum number of normal genes.

Euthanasia

The merciful hastening of death, often limited to willful and merciful actions to kill someone who is injured or terminally ill.

Exons

The protein-coding DNA sequences of a gene. Compare introns.

Exotic

Describing a species not originating in the place where it is found; a nonnative, introduced species.

Exotoxin

A poison excreted by some gram-negative or gram-positive organisms. It is composed of protein.

Extrachromosomal DNA

DNA not associated with the chromosome(s), for example, plasmid DNA or organelle (mitochondria or chloroplast) DNA).

Fallopian tube

Either of a pair of tubes that conduct the egg from the ovary to the uterus. Fertilization normally occurs within this structure. Blocked or scarred fallopian tubes are a leading source of infertility in women.

Fermentation

The process of growing microorganisms.

Fertility drugs

Compounds used to treat ovulatory dysfunction. These include clomiphene cityrate, human gonadotropins, bromocriptine, glucocorticoids and progesterone.

Fetus

The developing human embryo from the ninth week after fertilization until birth.

FDA

U. S. Food and Drug Administration.

Fertilization

The event that initiates the development of an oocyte into embryonic development; normally triggered by the entry of a sperm into the oocyte.

Fingerprinting

The technique of DNA fingerprinting is used to uniquely characterize individual organisms, foods or biological samples, based on their DNA composition (can also fingerprint chemicals and proteins).

Follicle

The structure on the ovary surface that nurtures a ripening oocyte. At ovulation the follicle produces estrogen until the oocyte is released, after which it becomes a yellowish protinsion on the ovary called the corpus luteum.

Food additive

A minor ingredient added to food to achieve a specific effect.

Frameshift

A mutation that results when the genetic code is read beginning at the second or third base of a codon.

Gamete intrafallopian transfer (GIFT)

A technique of medically assisted conception in which mature oocytes are surgically removed from a woman's body and then reintroduced, together with sperm, through a catheter threaded into the fallopian tubes, where it is hoped fertilization will take place.

Gamete

Mature male or female reproductive cell with a haploid set of chromosomes (in humans there are 23 chromosomes); that is, a sperm or ovum.

Gene

The fundamental physical and functional unit of heredity. A gene is an ordered sequence of nucleotides located in a particular position on a particular chromosome. See gene expression.

Gene expression

The process by which a gene's blueprint is converted into the structures and protein used by the cell to survive and performs its functions within an organism. Expressed genes include those that are transcribed into RNA and then translated into protein and those that are transcribed into RNA but not translated into protein (e.g., transfer and ribosomal RNAs).

Gene families

Groups of closely related genes that make similar products.

Gene product

The biochemical material, either RNA or protein, made by a gene. The amount of gene product is used to measure how active a gene is; abnormal amounts can be correlated with disease-causing genes.

Genetic code

The sequence of nucleotides, coded in triplets along the mRNA, that determines the sequence of amino acids in protein synthesis. The DNA sequence of a gene can be used to predict the mRNA sequence, and the genetic code can, in turn, be used to predict the amino acid sequence.

Genetic linkage map

A map of the relative positions of genetic loci on a chromosome, determined on the basis of how often the loci are inherited together. Distance is measured in centimorgans.

Genetic screening

Analysis of an individual genotype for the presence or absence of a particular DNA sequence, or gene.

Genetics

The study of patterns of inheritance of specific traits and their underlying basis.

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 the genome of human beings and other organisms.

Genomic library

A collection of clones made from a set of overlapping DNA fragments representing the entire genome of an organism. Compare library.

Genotype

The genetic constitution of an individual.

Germplasm

The total genetic variability, represented by germ cells or seeds, available to a particular population of organisms.

Germ cells

Egg and sperm cells and the cells that give rise to them.

GIFT

Gamete intrafallopian transfer, see above.

Gram-negative/positive

A classification of bacteria based on differential staining utilizing the Gram-Wiegert procedure. Primarily as a result of an organism's cell membrane structure, gram-negative organisms stain red and gram-positive organisms stain purple.

Gynecology

The branch of medicine that deals with diseases of the female reproductive tract.

Haploid

A single set of chromosomes (half the full set of genetic material), present in the egg and sperm cells of animals and in the pollen cells of plants. Human beings have 23 chromosomes in their reproductive cells. Compare diploid.

Health

A state of physical, mental and spiritual well-being.

Heterozygous

Having two different alleles at the same position on each of a pair of chromosomes.

Histocompatible

The condition in which tissues will not react to produce a rejection during transplantation.

HIV

Human immunodeficiency virus, a causative agent in the disease AIDS.

Homologous recombination

A process of DNA exchange where introduced DNA is substituted for native DNA containing identical or very similar (homologous) nucleotide base sequences at the edges of the exchanged regions.

Homologous sequence

Nucleic acid segments that have an identical or nearly identical linear order of nucleotide base pairs.

Homology

Degree of relatedness in appearance, function or structure.

Homozygous

Degree of relatedness in appearance, function or structure; having identical alleles at the same position on each of a pair of chromosomes.

Homeo box

A family of genes characterized by a short stretch of nucleotides whose sequence is virtually identical in all the species that contain it. It has been found in many organisms, from fruit flies to humans. It appears to determine when particular groups of genes are expressed in the development of the fruit fly.

Horizontal transfer

The passage of genetic material from one organism to another via nonsexual mechanisms.

Hormone

Chemical substances produced in one part of the body that affect an organ or group of cells in another area of the body.

HUGO

Human Genome Organization, an international body to coordinate efforts to sequence the human genome.

Human gene therapy

Insertion of normal DNA directly into cells to correct a genetic defect.

Human Genome Initiative

Collective name for several projects begun in the mid 1980s in several countries, following the U.S. Department of Energy decision to 1) create an ordered set of DNA segments from known chromosomal locations, 2) develop new computational methods for analyzing genetic map and DNA sequence data, and 3) develop new techniques and instruments for detecting and analyzing DNA.

Hybridization

The process of joining two complementary strands of DNA, or of DNA and RNA, to form a double-stranded molecule.

Hydatidiform mole

A placental abnormality composed of grape-like clusters of chorionic villi. It is the product of an abnormal fertilization where placental tissue is formed without any embryo.

Hybridoma

A new cell resulting from the fusion of a particular (type of (immortal type of immortal tumor cell line), a myeloma, with an antibody-producing B lymphocyte. Cultures of such cells are capable of continuous growth and specific (i.e., monclonal) antibody production.

Ice-minus

A bacterium lacking a functional gene coding for a protein that promotes the formation of ice crystals by providing a physical nucleus around which ice crystallizes. The gene has been deleted from strains of Pseudomonas syringe, Pseudomonas fluorescens, and Erwinia herbicola.

Ice-plus

A bacterium with an intact, functional ice-nucleating gene.

Immunodeficiency

The state of substandard function of the immune system.

Immunosuppression

That state of diminished function of the immune system.

Informatics

The study of the application of computer and statistical techniques to the management of information. In genome projects, informatics includes the development of methods to search databases quickly, to analyze DNA sequence information, and to predict protein sequence and structure from DNA sequence data.

Implantation

The process by which the fertilized oocyte (zygote) becomes attached to the wall of the uterus (endometrium). It commences in the seventh day of human embryo development, and is completed by day 14.

In vitro

Literally "in glass;" pertaining to a biological process or reaction taking place in an artificial environment, usually a laboratory.

In vitro fertilization (IVF)

A technique of medically assisted conception (sometimes referred to as "test tube" fertilization) in which mature oocytes are removed from a woman's ovary and fertilized with sperm in a laboratory. See embryo transfer.

Invivo

Literally "in the living;" pertaining to a biological process or reaction taking place in a living cell or organism.

Infertility

Inability to conceive.

Intellectual property

That area of the law that involves patents, copyrights, trademarks, trade secrets and plant variety protection.

International technology transfer

Movement of inventions and technical know-how across national borders.

Intrauterine device (IUD)

Contraceptive device inserted through the cervix into the uterine cavity.

Introns

The DNA sequences interrupting the protein-coding sequences of a gene that are transcribed into mRNA but are cut off the message before it is translated into protein. Compare exons.

Invention

An original device, contraption or process developed after study and experiment. Genetically engineered animals, plants and micro-organisms have been recognized as patentable forms of biological invention in the United States, but this is not always the case in other countries, especially where animals are concerned.

IVF

In vitro fertilization.

Karyotype

A photomicrograph of an individual's chromosomes arranged in a standard format showing the number, size and shape of each chromosome; used in low-resolution physical mapping to correlate gross chromosomal abnormalities with the characteristics of specific diseases.

Laparoscopy

Direct visualization of the ovaries and the exterior of the fallopian tubes and uterus by means of a laparoscope (a long, illuminated instrument) introduced through a small surgical incision below the navel, to evaluate any abnormalities. Surgical procedures also may be performed using this method.

Legalism

The position that ethical action consists in strict conformity to law or rules; antinomianism, rules of practice, situationalism.

Library

A collection of clones in no obvious order whose relationship can be established by physical mapping. Compare genomic library.

Linkage:

The proximity of two or more markers (e.g., genes, RFLP markers) on a chromosome; the closer together the markers, the lower the probability that they will be separated during meiosis; hence, the greater the probability that they will be inherited together.

Locus

The position on a chromosome of a gene or other chromosome marker, and also the DNA at that position. Some restrict use of locus to regions of DNA that are expressed. See gene expression and alleles.

Marker

An identifiable physical location on a chromosome (e.g., restriction enzyme cutting site, gene, RFLP maker) whose inheritance can be monitored. Markers can be expressed regions of DNA (genes) or some segment of DNA with no known coding function but whose pattern of inheritance can be determined.

Maternal serum alpha-fetoprotein

A protein, secreted during gestation, used to predict fetal abnormalities such as spina bifida.

Meiosis

The process of two consecutive cell divisions in the diploid progenitors of sex cells. Meiosis results in four rather than two daughter cells, each with a haploid set of chromosomes.

Mendelian genetics

Classical method of observing inheritance of a trait(s) in the offspring of crosses between individuals differing in that trait(s); results in accordance with Mendel's laws.

Messenger RNA (mRNA )

A class of RNA produced by transcribing the DNA sequence of a gene. The mRNA molecule carries messages specific to each of the 20 amino acids. Its role in protein synthesis is to transmit instructions from DNA sequences (in the nucleus of the cell) to the ribosomes (in the cytoplasm of the cell).

Metaphysical

The principles underlying a particular subject or system of beliefs.

Microinjection

A technique used for the insertion of genes from one cell into another cell, in which highly purified copies of a specific gene of interest are injected into a cell. Copies of one specific gene of interest can be injected into a fertilized animal egg. The egg then is surgically implanted in a female animal's reproductive tract.

Microorganisms

Minute, microscopic or submicroscopic living organisms (e.g., bacteria, mycyoplasma and viruses).

Mitosis

A type of cell division that produces daughter cells that have the same number of chromosomes as the originating cells.

Monoclonal antibodies

Identical anitbodies that recognize a single, specific antigen and are produced by a clone of specialized cells.

Morula (the Latin for mulberry)

Once the proliferating cells from the fertilized egg compact, they appear at the 12-16-cell stage like a mulberry. Hence the name is applied to the embryo about three days after fertilization.

MRC

The Medical Research Council, for example, of the United Kingdom.

Multifactorial or multigenic disorders

See polygenic disorders.

Mutagen

An agent (e.g., ultraviolet light, X-rays and certain chemicals) that increases the frequency or extent of mutation.

Mutagenesis

A process that results in modification of a DNA sequence.

Mutation

Any change in DNA sequence that results in a new characteristic that can be inherited. Compare polymophism.

Negative eugenics

Policies and programs intended to reduce the occurrence of genetically determined disease.

Natural selection

The process of differential reproductive success by which genes in a population increase or decrease in frequency with the passage of generations, depending on their contribution to the survival of offspring in which they are carried; arguably the most important of the several mechanisms by which evolution takes place, discovered by Darwin.

Neural tube defect

A condition resulting from the failure of the neural tube to close during fetal development, resulting in spina bifida or anencephely.

NIH

National Institutes of Health, USA.

Nonmaleficence

The state of not doing harm or evil: compare beneficence.

Nontherapeutic

Something thatdoes not serve the purposes of treating an ailment in an individual patient.

Navelty

One of the criteria used in the evaluation of patent applications. To be accepted on the grounds of novelty, the invention or discovery being evaluated must be new and must not have previously existed through the work of others.

Nucleic acid

A macromolecule composed of sequences of nuceotide bases, DNA or RNA.

Nucleotide

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

Nucleus

The membrane-enclosed structure in eukaryotes that contains the chromosomes.

Obstetrics

The branch of medicine that deals with the management of pregnancy and childbirth.

Obviousness

Obviousness is one of the criteria used in the evaluation of patent applications. Obviousness addresses the degree of difference between the invention being evaluated and that which already is known and available.

Oligonucleotide

A short section of DNA.

Oligospermia

Scarcity of sperm in the semen.

Oncogene

A gene, one or more forms of which is associated with cancer. Many oncogenes are involved, directly or indirectly, in controlling the rate of cell growth.

Ontological

Refers to actual existence in reality as distinct from in thought or in the imagination.

Oocyte

The immature female germ cell. It is called an ovum when it matures after the penetration of the sperm during fertilization and the completion of the second meiotic division.

Organelle

A structure in the cytoplasm of a cell that is specialized in its ultrastructure and biochemical composition to serve a particular function (e.g., mitochondria, endoplasmic reticulum, chloroplast).

OTA

U.S. Office of Technology Assessment.

Ovaries

Paired female sex glands in which ova are developed and stored and the hormones estrogen and progesterone are produced.

Oviduct

Fallopian tube.

Ovum (pl., ova)

The female egg or oocyte, formed in an ovary.

Ovum donor

A woman who donates an ovum or ova to another woman.

Patent

A patent is a grant issued by different governments through a patent and trademark office that gives the patent owner the right to exclude all others from making, using or selling a patented invention within the country for the term of the patent (e.g., in the United States the term is 17 years).

Paternalism

The system of action in which one person treats another the way a father treats a child, striving to promote the other's good even against the other's wishes.

Pathogenic

Able to cause disease; often used to express inactivation or lethality.

Phenotype

The characteristics of individuals that result from the interaction of their genotypes and their environments.

Physical map

A map of the locations of identifiable landmarks on DNA (e.g., restriction enzyme cutting sites, genes, RFLP markers), regardless of inheritance. Distance is measured in base pairs. For the human genome, the lowest-resolution physical map is the banding patterns of the 24 different chromosomes; the highest resolution map would be the complete nucleotide sequence of the chromosomes.

Plant breeding

The development of plants with certain desirable characteristics, such as disease resistance as a result of cross-fertilization.

Plant variety

Cultivated plants that are clearly distinguishable from others by one or more characteristics and that, when reproduced, retain those distinguishing characteristics.

Plant variety protection

Patent-like protection for certain sexually produced plants. Plant variety protection is granted by many countries, and applies within those countries. It applies only if the holder ensures a reasonable commercial supply of that variety to all who want it.

Plasmid

An extrachromosomal, circular piece of DNA found in the cytoplasm that is capable of replicating and segregating independently of the host chromosome. See vector.

Pleiotropic effect

The production of several unrelated changes in the characteristics of a cell or organism by a single genetic change.

Polygenic disorders

Genetic disorders resulting from the combined action of alleles of more than one gene (e.g., heart disease, diabetes and some cancers). Although such disorders are inherited, they depend on the simultaneous presence of several alleles, thus the hereditary patterns are usually more complex than those of single-gene disorders. Compare single-gene disorders.

Polymerase

An enzyme that assembles a number of similar or identical subunits into a macromolecule (e.g. DNA polymerase and RNA polymerase).

Polymorphism

The difference in DNA sequence among individuals. Genetic variations occurring in more than 1 percent of a population would be considered useful polymorphisms for genetic linkage analysis. Compare mutation.

Polyploid

Having a chromosome number that is greater than two of the monoploid number. Polyploid oysters were among the first nonnaturally occurring, nonhuman, multicellular, living organisms to be declared patentable subject matter.

Positive eugenics

The achievement of systematic or planned genetic changes to improve individuals or their offspring.

Preembryo

The developing cells produced by the division of the zygote before the formation of the embryo proper at the appearance of the primitive streak. Also called pro-embryo.

Primer

A short piece of DNA that promotes DNA synthesis by providing a site for the action of the enzyme, DNA polymerase, to add nucleotides at one end of the primer.

Primitive streak

A piling up of cells on the caudal end of the embryonic disc, providing the earliest evidence of the embryonic axis and the formation of the embryo proper. In human embryos this begins to occur at about day 15.

Prior art

That which is already known or available, part of the criteria of obviousness used in evaluating patent applications.

Prokaryote

Cell or organism lacking membrane bound, structurally discrete nucleus and subcellular compartments. Bacteria are examples. Compare eucaryote.

Protein

A large molecule composed of chains of smaller molecules (amino acids) in a specific sequence; the sequence is determined by the sequence of nucleotides in the gene coding for the protein. Proteins are required for the structure, function and regulation of the body's cells, tissues and organs, and each protein has unique function. Examples are hormones, enzymes and antibodies.

Protoplast

A plant cell whose wall has been removed by enzymatic or mechanical means.

Recessive

A trait or condition that is expressed only in individuals who have two altered versions of a particular gene, one inherited from their mother, and one from their father.

Recombinant DNA

Hybrid DNA sequences assembled in vitro from different sources; or hybrid DNA sequences from the same source assembled in vitro in a novel configuration.

Recombinant DNA technologies

Procedures used to join DNA segments not usually enjoined in a cell-free system (an environment outside of a cell or organism). A recombinant DNA molecule can enter a cell and replicate there, either autonomously or after it has become integrated into a cellular chromosome.

Recombination

The formation of a new association of genetic material. It usually is applied to the process of meiosis, during a stage of which the genetic material packaged into gametes is mixed and reconstituted in any of an enormous number of possible combinations. It also is applied to genetic engineering.

Replication

The synthesis of new DNA strands from existing DNA. In human beings and other eukaryotes, replication occurs in the nucleus of the cell.

Resolution

Degree of molecular detail on a physical map of DNA, ranking from low to high.

Restriction enzyme, endonuclease

A protein that recognizes specific, short nucleotide sequences and cuts DNA at those sites. There are more than 400 such enzymes in bacteria that recognize more than 100 different DNA sequences. See restriction enzyme cutting site.

Restriction enzyme cutting site

A specific nucleotide sequence of DNA at which a restriction enzyme cuts the DNA. Some sites occur frequently in DNA, every several hundred base pairs, but others occur much less frequently, perhaps every 10,000 base pairs.

Retrovirus

A family of viruses whose genetic material is RNA and is further characterized by the presence of reverse transcriptase in the virion.

Reverse transcriptase

An enzyme capable of directing the production of a single-strange DNA copy from an RNA template.

RFLP, restriction fragment length polymorphism

Variation in DNA fragment sizes cut by restriction enzymes; polymorphic sequences that are responsible for RFLPs are used as markers on genetic linkage maps.

Ribosomal RNA (rRNA)

A class of RNA found in the ribosomes of cells.

Risk

The probability of adverse effects, their nature and their severity over a range of exposures.

Risk/Benefit

A decision-assisting process that attempts to identify, estimate and weigh all the risks and benefits associated with a particular action and to determine whether the overall benefit would be worth the associated risk.

RNA, ribonucleic acid

A chemical found in the nucleus and cytoplasm of cells, it plays an important role in protein synthesis and other chemical activities of the cell. The structure of RNA is similar to that of DNA. There are several classes of RNA molecules, including messenger RNA. transfer RNA, ribosomal RNA and other small RNAs, each of which serves a different purpose.

RU-486

The steriodal antiprogestin milepristone, which is capable of inducing early abortion by inhibitng the secretion of progesterone.

Safety

The reasonable certainty that no harm will result under expected conditions of use.

Seed

A mature ovule, consisting of an embryonic plat together with a store of food, all surrounded by a protective coat. A seed usually develops following the fertilization of an egg cell by a male generative cell from a pollen grain.

Selective advantage

An organism's increased probability of reproduction and producing offspring, conferred by its genetic characteristics.

Selective pressure

The influence of factors extrinsic to an organism (i.e., environmental factors) on its ability to compete with other organisms for reproductive success.

Semen

A fluid consisting of secretions from the male's seminal vesicles, prostate and from the glands adjacent to the urethra. Semen carries sperm and is ejaculated during intercourse.

Sex chromosomes

The X and Y chromosomes in human beings that determine the sex of an individual. Females have two X chromosomes in diploid cells; males have an X and a Y chromosome.

Sexual reproduction

Reproduction that occurs as a result of the interaction between the two sexes. In plants, sexual reproduction occurs when a female egg cell is fertilized by a male generative cell from a pollen grain. Examples of sexually reproduced plants are corn, wheat and sorghum.

Single-gene disorders

Hereditary disorders caused by a single gene (e.g., Duchenne muscular dystrophy, reinoblastoma, sickle cell disease). Compare polygenic disorders.

Site-directed mutagenesis

The modification of a DNA sequence at a location that is precisely controlled.

Situationalism

The position that ethical action must be judged in each situation guided by, but not directly determined by, rules.

Somatic cells

Any cells in the body except reproductive cells and their precursors.

Species

Taxonomic category subordinate to a genus composed of individuals with common characteristics that distinguish them from other groups of the same taxonomic level; in sexually reproducing organisms, a group of interbreeding natural populations that are genetically distinct from other such groups.

Species barrier

The idea that there is a natural barrier between species that preserves their integrity or identity. This idea has no known foundation in biology. The parameters that limit the ranges and variations of species are fluid and variable, and species exist as reproductive communities rather than as separate creatures.

Species integrity

The idea that a species has integrity as a biological unit. This would have to be based on the identity of the genetic material carried by the species. However, it is not clear how a species might be defined genetically, and this issue is the subject of debate among those seeking to understand the nature of species.

Sperm

The male reproductive cell, or gamete. Normal sperm have symmetrically oval heads, stout midsections and long, tapering tails.

Sperm bank

A place in which sperm are stored by cryopreservation for future use in artificial insemination.

Strain

A pure culture of organisms within a species, characterized by one or more particular physical or genetic properties.

Surrogate

Someone serving as a substitute decisionmaker.

Surrogate mother

A woman who is artificially inseminated, with sperm or embryo, and carries an embryo to term, with the intention of relinquishing the child at birth.

Syndrome

The combination of signs and symptoms that occur together in any particular disorder.

Syngamy

The mingling of the male and female haploid chromosome sets following the breakdown of the pronuclear membranes. This results in the formation of the zygote.

Syphilis

A sexually-transmitted disease caused by an organism called spirochete.

Technology transfer

The process of converting scientific knowledge into useful products.

Teleological

Explaining phenomena by their design, purpose or final causes.

Teratogenic

Producing malformation in an embryo or fetus.

Teratoma

A new and uncontrolled growth of cells and tissues that are the product of an abnormal fertilization without any potential to develop into an embryo proper or fetus.

Therapy

The provision of remedies in the treatment of disorders or illnesses.

Tissue culture

The propagation of tissue removed from organisms in a laboratory environment that has strict sterility, temperature and nutrient requirements.

Tissue plasminogen activator (tPA)

A genetically engineered protein drug that helps to dissolve blood clots in patients who have suffered heart attacks.

Totipotency

This represents the capacity (potential) of a cell or a cluster of cells to produce the whole (total) embryo and fetus with all its extra embryonic membranes and tissues. Pluripotency or multipotency is similar but is restricted to represent the capacity to produce a variety of parts and tissues but not the whole embryo and fetus.

Toxicity testing

The use of experimental procedures to determine the levels at which exposure to a material leads to adverse effects in test subjects, the characterization of such induced effects and the elucidation of mechanisms of action by which effects were induced.

Toxin

Most often, a toxic peptide or protein capable of eliciting anitbody production. A toxicant is a substance that has been shown to present some significant degree of possible risk when consumed above safe limits by animals. See endotoxin and exotoxin.

Transcription

The synthesis of mRNA from a sequence of DNA (a gene); the first step in gene expression. Compare translation.

Transduction

The transfer of genetic material from one cell to another by means of a virus or bacteriophage.

Transfer RNA (tRNA)

A class of RNA having structures with triplet nucleotide sequences that are complementary to the triplet nucleotide coding sequences of mRNA. The role of tRNAs in protein synthesis is to bond with amino acids and transfer them to the ribosomes, where proteins are synthesized according to the instructions carried by mRNA.

Transformation

Introduction and assimilation of DNA from one organism into another via uptake of naked DNA.

Transgenic animals

Animals whose hereditary DNA has been augmented by the addition of DNA from a source other than parental germ plasm, usually from another animal or a human, in a laboratory using recombinant DNA techniques. At the moment, most of the research in this field is conducted on mice, but major research efforts in transgenic animal modification also are focusing on cattle, pigs, sheep, poultry and fish.

Translation

The process in which the genetic code carried by mRNA direct the synthesis of proteins from amino acids. Compare transcription.

Translocation

The transfer of genetic material from one chromosome to another. An exchange of material between two chromosomes is referred to as a 'reciprocal translocation.'

Transposable element

A class of DNA sequences capable of insertion into a genome at numerous positions, and moving from one area of a genome to another area or to another genome.

Transposon

A type of transposable element incapable of autonomous existence, often shuttling genetic material back and forth between cell chromosomes, between smaller replicons, and between chromosomes and replicons.

Ultrasound

The use of high-frequency sound waves focussed on the body to obtain a video image of internal tissues and organism structures. Ultrasound is particularly useful for in utero examinations of a developing fetus, for evaluation of the development of ovarian follicles, and for the guided retrieval of oocytes for IVF and GIFT.

Utilitarian

The view that an action is deemed morally acceptable because it produces the greatest balance of good over evil taking into account all individuals affected.

Utility

The state of being useful or producing good.

Utility patents

Usefulness or utility is one of the criteria used to evaluate patent applications. Utility patents are issued to inventors of any new and useful process, machine, manufacture or composition or any new and useful improvement thereof.

Vasectomy

Sterilization of a man by surgical excision of a part of the vas deferens.

Vector

DNA molecule originating from a virus, a bacterium or the cell of a higher organism used to carry additional DNA base pairs; vectors introduce foreign DNA into host cells, where it can be reproduced in large quantities. Examples are plasmids, cosmids and yeast artificial chromosomes.

Virus

Any of a large group of organisms containing genetic material but that are unable to reproduce outside a host cell.

Wild-type

An organism isolated from nature.

X-linked

Genes carried on the X chromosome.

Zona pellucida

A thick, transparent noncellular layer of uniform thickness surrounding the oocyte, zygote and early embryo for several days, when it degenerates and allows the embryo to everge or hatch out.

Zygote

The fertilized egg; the single cell that is formed when the two haploid sets of chromosomes in the pronuclei of the male and female gametes come together at syngamy. Also used loosely to referred to as the early embryo during the first few weeks.