| Allele | A technical term meaning an alternative form of a gene. Each of us has two copies of every gene in the genome. One copy is inherited from the father and the other from the mother. Thus, every gene in a human cell is present in two copies, which may be identical or slightly different versions |
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| Assay | A biological test, measurement or analysis |
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| Base | The simplest building block component of DNA. Each base is a chemical call a nucleotide and there are 4 base types whose names are Adenine, Cytosine, Guanine and Thymine, abbreviated as A,C,G and T |
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| Base Pair | A pair of any two of the four bases. The chemical structure of the bases allows them to attract each other, and hence to pair up. A always pairs with T and C pairs with G. The double helix form of DNA therefore consists of two equal and opposite strands in which the bases pair up in this way across the helix |
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| Bioinformatics | The use of computer technology to process, store, retrieve and analysis biological information in a high throughput manner. It is used particularly for automated comparison of experimental data with large public sector databases of gene and protein sequences |
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| Candidate Genes | Genes suspected of having a role in the disease process on the basis of their known biological function. Such genes, and variations within them, can be tested to see if they occur more often in affected individuals |
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| Chromosome | A package of DNA consisting of a string of genes in a thread-like format contained within the nucleus of cells. The human genome is packaged into 23 chromosomes, each of which is present in two copies within most cells |
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| Cloning | The process of producing a group of cells, all genetically identical, from a single ancestor. The resultant cells are known as clones of the ancestor. In genomices, this is a commonly used DNA manipulation procedure to produce multiple copies of a single gene or a segment of DNA is referred to as cloning DNA. The copies are grown in bacterial cells and not used in any way for the production of animals or manipulation of human embryos |
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| Disease | Association Proof that a gene can be directly correlated to suscepibility for, or progression of, a particular disease or condition |
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| DNA | Deoxyribonucleic Acid - is the molecule that carries genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs. Thus the DNA sequence of bases of each single strand can be deduced from that of its' partner |
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| DNA Micro-array Hybridisation | A technique used to lay out a large number of DNA samples as an array of individual spots on a glass slide or nylon membrane. It is used to compare the content of DNA sequences between one sample and another e.g comparing diseased tissue against normal |
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| DNA Sequencing | The process of determining the order of the bases that make up a strand of DNA |
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| Functional Genomics | A wide ranging set of biological techniques which are used to identify or confirm the biochemical role of a newly discovered gene within the cells and to understand how this role might be related to disease pathways |
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| Gene | The basic unit of heredity; each gene can be composed of up to 5,000 bases in sequence occupying a specific location on a chromosome. The DNA sequence of the gene codes (i.e causes the formation of a single protein) |
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| Gene Expression | The process by which a gene is activated and the DNA code of that gene is translated into a specific protein |
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| Gene Mapping | The process of identifying and locating the position of a gene on a particular chromosome within the genome |
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| Genome | The entire genetic makeup (the full complement of DNA, including all the genes) of an individual or organism. The humun genome comprises of approximately 3 billion bases and 100,00 genes |
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| Genomics | The use of modern high throughput methods on analysis to study the total genome in order to identify diseae-causing genes and understand their function in cells so as to develop new therapeutics and diagnostics |
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| Genotyping | The process of analysing the particular variations (polymorphisms) existing in an individual DNA sample |
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| Haplotype | A technical term for a set of two alleles (gene variants) at two or more closely linked positions on a chromosome |
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| omozygote | An individual having two identical alleles of a given gene |
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| Human Genome | Major international project to define the precise sequence of all the project bases (3 billion in total) making up the human genome |
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| Junk DNA | Stretched of DNA that do not represent genes and with no known function. Originally thought to be purely structural, but now believed to play a significant role in controlling gene expression |
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| Mutation | Any observable, spontaneous change in an inherited characteristic resulting from a change in the base sequence of DNA. Such effects may result from changes ranging from single base substitutions, up to major chromosomal rearrangements |
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| Nucleotide | term for a base |
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| Phenotype | Physical, clinical or biological characteristics of an organism, determined by the interaction of it's genetic make-up with the enviroment |
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| Polymorphism | A region of DNA (either within a gen or outside) having a change or difference in the sequence of bases from one individual to another i.e. a variable region of DNA. Where these occur in the gene, they may be responsible for a difference in the protein production of that gene, giving rise to disease. |
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| Postional Cloning | The process of identifying and cloning a disease gene based on it's location in the genome rather than it's biological function. Usually involves intensively mapping sequencing stretches of DNA within linkage regions in order to narrow down the chromosomal region likely to contain the gene to a length of 500,000 bases or less |
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| Proteomics | The study of the total protein content of cells and the products of genes so as to indentify differences between normal and diseased tissue and to relate these differences to the disease pathways |
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| RNA | Ribonucleic Acid, the structure of RNA is similar to that of DNA but a slight change in the chemical structure of the nucleotides makes RNA more stable. It plays an important role in protein synthesis and other chemical activities within the cell where it helps translate DNA sequences into proteins. It is therefore found in both the nucleus and cytoplasm of cells |
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| Single Nucleotide Polymorphism(SNP | A polymorphism represented by the change of one base or nucleotide within the sequence of a DNA strand. MAy occur within gened or outside them |
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| SNP detection | Locating SNP's within a known gene |
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| SNP mining | Locating SNP's at random accross a length of DNA that may or may not contain genes |
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| SNP identification | Determining the sequence of a particular SNP or SNP's within a gene |
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| SNP typing/scoring | Determining the SNP profiles of a group of individuals for a panel of known SNP's at particular locations |
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