All definitions are taken from the Genomics Lexicon.
DNA (deoxyribonucleic acid): the molecule that encodes genetic information. DNA is a double-stranded helix held together by bonds between pairs of nucleotides
Enzyme: a protein that facilitates a biochemical reaction in a cell. In general, these biochemical reactions would not occur if the enzyme is 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.
Gene: a length of DNA which codes for a particular protein, or in certain cases a functional or structural RNA molecule.
Genetic map: a map of a genome which shows the relative positions of the genes and/or markers on the chromosomes.
Genetic marker; see marker
Genetic testing: the analysis of an individual's genetic material. Among the purposes of genetic testing could be to gather information on an individual's genetic predisposition to particular health condition, or to confirm a diagnosis of genetic disease.
Genomics: the study of 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 healthcare 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.
Marker: 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/or it can be used to distinguish among cell types. A marker may or may not be part of a gene. Markers are essential for use in linkage studies and genetic maps to help scientists to narrow down the possible location of new genes, and to discover the associations between genetic mutations and disease.
Nucleic acid: one of the family of molecules which 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. See nucleotide.
Nucleotide: 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, while in RNA (a DNA-related molecule which 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."
Polymerase chain reaction (PCR): a method for creating millions of copies of a particular segment of DNA. If a scientist needs to detect the presence of a very small amount of a particular DNA sequence, PCR can be used to amplify the amount of that sequence until there are enough copies available to be detected.
Restriction enzyme cutting site: A specific nucleotide sequence of DNA at which a particular restriction enzyme cuts the DNA. Some sites occur frequently in DNA (e.g., every several hundred base pairs), others much less frequently (rare-cutter; e.g., every 10,000 base pairs).
Restriction enzyme: A protein that recognizes specific, short nucleotide sequences and cuts DNA at those sites. Bacteria contain over 400 such enzymes that recognize and cut over 100 different DNA sequences. See restriction enzyme cutting site.
|