Library
An unordered collection of clones (i.e, cloned DNA from a particular organism ) whose relationship to each other can be established by physical mapping. See also: genomic library, arrayed library.

Ligand
A molecule that binds to a receptor.

Ligase
An enzyme that catalyzes the formation of a phosphodiester bond between adjacent 3'-OH and S'-P atoms in DNA.

3. A condition in which two non-allelic genes tend to be inherited together. Linked genes are found on the same chromosome and do not assort independently, but can be separated by crossing over.
4. The greater association in inheritance of two or more nonallelic genes than is to be expected from independent assortment; genes are linked because they reside on the same chromosome.

Linkage disequilibrium
A condition in which the haplotype frequencies in a population deviate from the values they would have if the genes at each locus were combined at random. (When no deviation exists, the population is said to be in linkage equilibrium).
2. Where alleles occur together more often than can be accounted for by chance. Indicates that the two alleles are physically close on the DNA strand. See also: Mendelian inheritance.

Linked
Of genes, present on the same chromosome

LinkedGenes (Linked Markers)
Genes and / or markers that are closely associated on a chromosome. This determination is usually by means of linkage analysis, but may also be inferred if the markers are in linkage disequilibrium.

Linnaean classification
A hierarchical method of naming classificatory groups, invented by the eighteenth century Swedish naturalist Carl von Linne, or Linnaeus. Each individual is assigned to a species, genus, family, order, class, phylum, and kingdom, and some intermediate classificatory levels. Species are referred to by a Linnaean binomial of its genus and species, such as Magnolia grand flora.