Genetic and Medical Glossary

the abbreviation for guanine, a purine nitrogenous base found in the structure of both DNA and RNA

series of dark and light stripes across a chromosome which are produced by treating (staining) the chromosomes with different chemicals in a laboratory

mutations that change the gene product such that it gains a new and abnormal function and usually have dominant phenotypes

disorder is characterized by adenomatous polyposis, an association of numerous polyps of the colon with soft tissue tumors, mostly in the brain and thyroid; also present are osteomas, causing susceptibility to colon cancer; congenital hypertrophy of the retinal pigment epithelium, jaw and/or sebaceous cysts

condition in which the stomach contents leak backwards from the stomach into the esophagus (the tube from the mouth to the stomach)

a portion of a DNA molecule containing the genetic information necessary to produce a molecule of messenger RNA (via transcription) that can then be used to produce a protein (via translation)

the combined biochemical processes (transcription and translation) that convert the linearly encoded information in the bases of DNA into the three-dimensional structures of proteins

multiple copies of the same or similar genes in the same genome; copies can be identical and tandemly repeated, or may differ slightly and be scattered on the same or different chromosomes

determining the relative locations of different genes on chromosomes

the complete assortment of genes present in the gametes of the members of a population that are eligible to reproduce

any form of genetic regulation in which the expression of a gene is completely repressed, either by preventing transcription or after a messenger RNA (mRNA) has been transcribed

any procedure that genetically alters the cells of the person to alleviate or treat the symptoms of a disease or condition

information contained in the DNA which is ‘interpreted’ by the cells to produce proteins; nucleotides which make up DNA are described by the letters A (adenine), T (thymine), C (cytosine) and G (guanine); written in a series of these letters in triplicate

a discipline concerned with analyzing the inheritance patterns of a particular genetic defect within a given family, including the determination of the risk associated with the presence of a genetic defect in future generations and options for treatment of the existing genetic defect

the testing of individuals for disease-causing genes or genetic disease

the use of techniques of genetics research to determine a person’s risk of developing, or status as a carrier of, a disease or other disorder

a branch of biology involving the study of heredity

complete set of genes carried by an individual or all the DNA in the cell or in one of the organelles (eg, mitochondrion)

a genetic phenomenon in which the phenotype associated with a particular allele depends on which parent donated the allele

branch of genetics dealing with the study of genetic sequences, including their structure and arrangement

the genetic characteristics of a cell or organism, expressed as a set of symbols representing the alleles present at one or more loci (sites)

phenotype is the constellation of observable traits; genotype is the genetic endowment of the individual. Genotype is the set of genes responsible for a particular trait, phenotype is the physical expression of that trait

when germ cells (sperm or egg cells) have a different genetic makeup from cells in the rest of the body

heritable change in the genes of an individual’s reproductive cells, often linked to hereditary diseases

smooth part of the forehead above and between the eyebrows

condition of increased pressure within the eyeball, causing gradual loss of sight

formation of fibrous tissue in the renal glomerulus as a result of repair or a reactive process

posterior displacement of the tongue into the pharynx

disorder characterized by hemifacial microsomia (hypoplasia of one side of the face), epibulbar dermoid (benign tumors over the cornea and sclera), and absence or severe hypoplasia of one ear

congenital developmental disorder of the reproductive organs

generation and development of the gonads (organ that produces testes or ovaries)

autosomal dominant genetic disorder characterized by a broad face, rib malformations, and high susceptibility to basal cell carcinoma, a type of skin cancer

genetic disorder characterized by physical abnormalities affecting the fingers and toes and the head and facial (craniofacial) area; extra (supernumerary) fingers and/or toes (polydactyly), webbing and/or fusion of the fingers and/or toes (syndactyly) may be present; craniofacial malformations may include a large and/or unusually shaped skull, high, prominent forehead (frontal bossing), abnormally broad nasal bridge, and widely spaced eyes (ocular hypertelorism)

a purine nitrogenous base found in the structure of both DNA and RNA

convolutions on the surface of a cerebral hemisphere produced by the infolding of the cerebral cortex