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ALSO KNOWN AS: Chromosomal instability, CIN

Genomics grew out of the field of genetics, the study of heredity. Until the late twentieth century, it had not been possible to study the complete set of hereditary information in a living organism. Thus, while the field of genetics traces its roots to the 1860s when the Austrian monk Gregor Mendel performed experiments on the mechanism of heredity in pea plants, the field of genomics is much younger, dating from the 1980s. It was in this decade that American geneticist Thomas Roderick used the term genomics to name a new scientific journal that dealt with the analysis of genomic information. In Mendel’s time, while organisms were seen to exhibit certain traits, it was not known how these traits were determined. By the early twentieth century, it was recognized that traits are inherited in units of information called genes, although the chemical nature of the gene was still unknown. It took until the middle of that century to recognize that genes were made up of deoxyribonucleic acid (DNA), the structure of which was first identified by American biologist James Watson and British biophysicist Francis Crick in 1953.

ALSO KNOWN AS: 4p-syndrome; monosomy 4p; del(4p); includes Pitt-Rogers-Danks syndrome

DNA analysis is, in the strictest sense of the term, an actual observation of the length or sequence of a portion of DNA. The length of a fragment of DNA can be determined using gel electrophoresis. This technique involves placing DNA onto a semisolid support, or gel, and applying an electric current to the gel so that DNA migrates toward the positive pole. The migration of DNA in gel electrophoresis is proportional to its mass, which is, in turn, proportional to its length. Determining the actual sequence of bases in a strand of DNA is much more complicated.

DEFINITION: Extraction of biological resources from areas of biodiversity

Biotechnology can be defined as the use of living organisms to achieve human goals; in this sense, humans have used biotechnology throughout history to provide themselves with such things as food, clothing, shelter, cosmetics, and medicine. Starting around 10,000 b.c.e., humans began to alter the genetic makeup of the plants and animals that they used by artificially selecting certain traits in the crops and livestock that they were breeding. Because farmers lived in different areas around the world with varying environmental conditions, the varieties of domesticated organism that eventually developed initially preserved what is known as “ genetic diversity.” Every organism on Earth has a particular genome, its entire set of DNA, which is specific to that particular living thing. Therefore, genetic diversity is at its greatest when the widest variety of organisms available are in existence in a particular area. The term “ biodiversity” refers to the number of different species (or other taxonomical units) that inhabit a given ecosystem or geographical area.

DEFINITION: Determination of the number of repetitive DNA sequences two to seven base pairs in length that are found at particular locations on chromosomes in long arrays, the exact number of which typically varies among individuals in a population.