Genetic linkage

Genetic Linkage and Genetic Maps
The Background
Gregor Mendel analyzed the pattern of inheritance of seven pairs of contrasting traits in the domestic pea plant.

Genetic linkage maps of each chromosome are made by determining how frequently two markers are passed together from parent to child.

Genetic linkage map. A linear map of the relative positions of genes along a chromosome. Distances are established by linkage analysis, which determines the frequency at which two gene loci become separated during chromosomal recombination.

[edit] Genetic linkage
Genetic linkage occurs when the loci of two alleles are linked, or in close proximity to each other on the chromosome.

Genetic linkage map -- a chromosome map showing the relative positions of the known genes on the chromosomes of a given species.

A centimorgan is a unit used to measure genetic linkage. One centimorgan equals a one percent chance that a marker on a chromosome will become separated from a second marker on the same chromosome due to crossing over in a single generation.

Information gathered on individual clones from various genetic linkage and physical map analyses is entered into a relational database and used to construct physical and genetic linkage maps simultaneously; ...

A key discovery of classical genetics in eukaryotes, was genetic linkage.

Variation between individuals in DNA fragment sizes cut by specific restriction enzymes; polymorphic sequences that result in RFLPs are used as markers on both physical maps and genetic linkage maps.

many situations ranging from genetic traits or disorders in a population to the variation in the sequence of DNA or proteins. Genetic variations occurring in more than 1% of a population would be considered useful polymorphisms for genetic linkage ...

by a particular enzyme the fragment sizes will differ depending on the presence or absence of the proper recognition sequence for the enzyme. Polymorphic sequences that result in RFLPs are used as markers on both physical maps and genetic linkage ...

Information gathered on individual clones from physical map analyses is entered into a relational database and used to construct physical and genetic linkage maps simultaneously; clone identifiers serve to interrelate the multilevel maps. Cf.

in the construction of clone based maps and in mapping by the use of irradiation hybrids. An EST may be an STS if it can be amplified from genomic DNA. Some STSs contain a polymorphic microsatellite and can thus also be positioned on genetic linkage ...

See also: Linkage, DNA, Chromosome, Sequence, Genome