LD

(LD): The tendency for two 'alleles' to be present on the same chromosome (positive LD), or not to segregate together (negative LD). As a result, specific alleles at two different loci are found together more or less than expected by chance. The same situation may exist for more than two alleles. Its magnitude is expressed as the delta value and corresponds to the difference betweenthe expected and the observed haplotype frequency. It can have positive or negative values. LD is decreased by recombination. thus, it decreases every generation of random mating unless someprocess opposing the approach to linkage equilibrium. Permanent LD may result from natural selection if some gametic combinations result in higher fitness than other combinations. Link to a lecture onlinkage disequilibrium.

1. Light Amplification by Stimulated Emission of Radiation. Tiny salt-grain sized semiconductor devices giving out intense light at one specific color when an electric current is passed through them. Used to transmit information in an optical network. 2. A semiconductor that emits coherent light when forward biased.