Allele: An alternative form of a gene or any other segment of a chromosome.
Bioinformatics: The analysis of biological information using computers and statistical techniques; the science of developing and utilizing computer databases and algorithms to accelerate and enhance biological research.
Biomarker: A molecular indicator of a specific biological property; a biochemical feature or facet that can be used to measure the progress of disease or the effects of treatment.
Complementary DNA (cDNA): DNA made from a messenger RNA (mRNA) template. The single-stranded form of cDNA is often used as a probe in physical mapping.
DNA (deoxyribonucleic acid): One of two types of molecules that encode genetic information. (The other is RNA. In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.)
Expressed sequence tag: A unique stretch of DNA within a coding region of a gene that is useful for identifying full-length genes and serves as a landmark for mapping.
Gene: The basic biological unit of heredity; a segment of deoxyribonucleic acid (DNA) needed to contribute to a function.
Genome: All of the genetic information or hereditary material possessed by an organism; the entire genetic complement of an organism.
Genomics: The study of genes.
Genotype: The genetic composition of an organism or a group of organisms; a group or class of organisms having the same genetic constitution.
In vitro: Literally, “in glass,” i.e., in a test tube or in the laboratory; the opposite of in vivo (in a living organism).
In vivo: In a living organism, as opposed to in vitro (in the laboratory).
Knockout: Inactivation of specific genes. Knockouts are often created in laboratory organisms such as yeast or mice so that scientists can study the knockout organism as a model for a particular disease.
Mapping: Charting the location of genes on chromosomes.
Mass spectrometry: A method used to determine the masses of atoms or molecules in which an electrical charge is placed on the molecule and the resulting ions are separated by their mass to charge ratio.
Messenger RNA (mRNA): A type of RNA that reflects the exact nucleoside sequence of the genetically active DNA. mRNA carries the "message" of the DNA to the cytoplasm of cells where protein is made in amino acid sequences specified by the mRNA.
Metabonomics: The evaluation of tissues and biological fluids for changes in metabolite levels that result from toxicant-induced exposure.
Microarray: A tool used to sift through and analyze the information contained within a genome. A microarray consists of different nucleic acid probes that are chemically attached to a substrate, which can be a microchip, a glass slide or a microsphere-sized bead.
Northern blot: A technique used to separate and identify pieces of RNA.
Nucleotide: A subunit of DNA or RNA. To form a DNA or RNA molecule, thousands of nucleotides are joined in a long chain.
Phenotype: The observable physical or biochemical traits of an organism, as determined by genetics and the environment; the expression of a given trait based on phenotype; an individual or group of organisms with a particular phenotype.
Polymorphism: The quality or character of occurring in several different forms.
Proteome: All of the proteins produced by a given species, just as the genome is the totality of the genetic information possessed by that species.
Proteomics: The study of the proteome.
RNA (ribonucleic acid): A nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose.
Signal transduction pathway: The course by which a signal from outside a cell is converted to a functional change within the cell.
Single nucleotide polymorphism (SNP): A change in which a single base in the DNA differs from the usual base at that position.
Throughput: Output or production, as of a computer program, over a period of time.
Toxicology: The study of the nature, effects and detection of poisons and the treatment of poisoning.
Toxicogenomics: The collection, interpretation, and storage of information about gene and protein activity in order to identify toxic substances in the environment, and to help treat people at the greatest risk of diseases caused by environmental pollutants or toxicants.
Transgenic: Having genetic material (DNA) from another species. This term can be applied to an organism that has genes from another organism.