Dictionary

genetic Having to do with genes and genetic information.

general paresis Progressive dementia and generalized paralysis due to chronic inflammation of the covering and substance of the brain (meningoencephalitis). General paresis is a part of late (tertiary) syphilis and is very rare today. It occurs a decade or more after the initial infection.

gene therapy The treatment of disease by replacing, altering, or supplementing a gene that is absent or abnormal and that is responsible for the disease.

gene testing The testing of a sample of blood (or another fluid or tissue) for evidence of a gene. The aim of gene testing is usually to learn whether a gene for a disease is present or absent.

gene product The RNA or protein that results from the expression of a gene. The amount of gene product is a measure of the degree of gene activity.

gene marker A detectable genetic trait or distinctive segment of DNA that serves as a landmark for a target gene. Markers are on the same chromosome as the target gene. They must be near enough to the target gene to be genetically linked to it and to be inherited, usually together with that gene, and…

gene mapping The charting of the positions of genes on a DNA molecule or chromosome and the distance, in linkage units or physical units, between genes.

gene family A group of genes that are related in structure and often in function. The genes in a gene family are descended from an ancestral gene. For example, the hemoglobin genes belong to one gene family that was created by gene duplication and divergence.

gene expression The translation of information encoded in a gene into protein or RNA structures that are present and operating in the cell. Expressed genes include genes that are transcribed into messenger RNA (mRNA) and then translated into protein, as well as genes that are transcribed into RNA, such as transfer and ribosomal RNAs, but…

gene duplication An extra copy of a gene. Gene duplication is a key mechanism in evolution. After a gene is duplicated, the once-identical genes can undergo changes and diverge to create two different genes.

gene deletion The total loss or absence of a gene. Gene deletion plays a role in birth defects and in the development of cancer.

gene, zygotic lethal A gene that is fatal for the zygote, the cell formed by the union of a sperm and an egg. The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene kills prenatal development at its earliest point. A zygotic…