Analysis, linkage: Study aimed at establishing linkage between genes. Today linkage analysis serves as a way of gene-hunting and genetic testing.
Linkage is the tendency for genes and other genetic markers to be inherited together because of their location near one another on the same chromosome.
A gene is a functional physical unit of heredity that can be passed from parent to child. All genes in humans are pieces of DNA. Most genes contain information for making a specific protein.
The term “genetic marker” is broader than a gene. A genetic marker is simply a segment of DNA with an identifiable physical location on a chromosome whose inheritance can be followed. A genetic marker can have a function and thus be a gene. Or a marker can be a section of DNA with no known function.
Because DNA segments that lie near each other on a chromosome tend to be inherited together, markers are often used as tools for tracking the inheritance pattern of a gene that has not yet been identified but whose approximate location is known.
The statistical estimate of whether two loci are likely to lie near each other on a chromosome and are therefore likely to be inherited together is called a LOD score. A LOD score of 3 or more is generally taken to indicate that the two loci are linked and are close to one another.
- Analytic sensitivity
Analytic sensitivity: The lowest level of a substance that can be detected by an analytic method.
- Analytic specificity
Analytic specificity: How well an assay detects only a specific substance and does not detect closely related substances.
Anaphia: The inability to feel touch. From the Greek prefix an, not + Greek haphe, touch = inability to (feel) touch. A person with anaphia is said to be anaptic.
- Anaphylactic shock
A widespread and very serious allergic reaction. Symptoms include dizziness, loss of consciousness, labored breathing, swelling of the tongue and breathing tubes, blueness of the skin, low blood pressure, heart failure, and death. Immediate emergency treatment is required for this type of shock, including administration of epinephrine in the case of bee or wasp stings.
- Anaphylactoid purpura
Anaphylactoid purpura: A form of blood vessel inflammation that affects small capillaries in the skin and the kidneys. It results in skin rash associated with joint inflammation (arthritis) and cramping pain in the abdomen. Anaphylactoid purpura frequently follows a bacterial or viral infection of the throat or breathing passages, and it is an unusual reaction […]