What is linkage disequilibrium?
Linkage Disequillibrium (LD) is the term used in population genetics for the non random association of alleles at different loci in a given population.
Loci are said to be in disequilibrium when the frequency of association of their different alleles is higher or lower than what would be expected if the loci were independent and associated randomly. When alleles are in LD, haplophytes do not occur at the expected frequencies.
LD is a sensitive indicator of the population genetic forces that structure a genome. The pattern of LD in a genome is a powerful signal of the population genetic process that are structuring it.
LD provides information about past events and it constraints the potential response to both natural and artificial selection. It is an important concept in genetic studies that aim to identify and/or localise genes related to disease susceptibility. LD between two alleles is related to the time of the mutation events, genetic distance and population history.