Glossary

A genomic marker (or genetic marker) is a specific gene or DNA sequence that is associated with a known characteristic. They are used to study the relationship between diseases and genetics. A genetic marker can serve as a flag for another gene. It must be on the same chromosome and near enough to the other gene that the two genes are genetically linked and are usually inherited together.

Genomic technologies are those new methods, technologies, and instruments used to study and manipulate the genome.

Genomics is the branch of biology that studies the entire genome of an organism by sequencing, assembling, and analysing the function and structure of its DNA. Advances in genomics have allowed great progress to be made in understanding diverse illnesses.

Genomics research can develop more effective therapeutic strategies, and better decision-making tools for patients and healthcare providers.

A genotoxicity study is designed to detect compounds that cause genetic damage either directly or indirectly in cells exposed to the toxic substrates. Genotoxicity studies may be performed in vitro or in vivo.

Compounds which are positive in tests that detect such damage have the potential to cause cancer and/or heritable defects. No single test is capable of detecting all relevant genotoxic agents therefore, the usual approach is to carry out a battery of tests that are complementary rather than representing different levels of hierarchy.

A standard study battery has the following tests:

1. A test for gene mutation in bacteria,
   
2. An in vitro test with cytogenetic (concerned with the study of the structure and function of the cell) evaluation of chromosomal damage with mammalian cells,
   
3. An in vivo test for chromosomal damage using rodent haematopoietic (blood or blood cell forming) cells.
   

A chemical or other agent that provokes a harmful change in a person™s genetic material regardless of the mechanism by which the change is induced. A genotoxin can cause mutations in DNA (a mutagen), it can trigger cancer (a carcinogen), or it can cause a birth defect (a teratogen).

The genotype is an individual's collection of genes, including which genetic variants they have. It is the entire complex of genes inherited from both parents. The genotype determines the hereditary characteristics of an individual. A genotype can be determined by sequencing an individual™s genome.

Genotyping is the process of determining differences in the genetic make-up or genotype of an individual by examining their individual DNA sequence. This can be done by comparing one person's genotype to another individual's sequence, or against a reference sequence.

In medicines development, the gold standard often refers to the best available therapy/product/treatment. Depending on the context, the gold standard may also mean different things. In clinical design, a double-blind, randomised

trial is seen by many as the gold standard.

The gold standard may change over time as new methods/treatments/medicines become available. For example, the gold standard test for the diagnosis of aortic dissection (a tear inside the aorta) used to be the aortogram, which had a sensitivity as low as 83% and a specificity as low as 87%. Now, the magnetic resonance angiogram (MRA) is seen by many as the new gold standard test for aortic dissection, with a sensitivity and a specificity both over 90%.

Good Clinical Practice (GCP) is an international ethical and scientific quality standard for designing, conducting, recording and reporting clinical trials that involve human participants. The International Conference on Harmonisation (ICH) has issued a guideline with the objective to provide a unified standard to facilitate the mutual acceptance of clinical data by the regulatory authorities in the jurisdictions pertaining to the ICH.

Good Distribution Practice (GDP) is a standard ensuring that the quality of a medicine is maintained throughout the distribution network, so that authorised medicines are distributed to retail pharmacists and others selling medicines to the general public without any alteration of their properties.