Linkage disequilibrium patterns vary substantially among populations:
…Analyses of these three genomic regions provide empirical demonstration of marked differences in frequencies of the same few haplotypes, resulting in differences in the amount of LD and very different sets of haplotype frequencies. These results highlight the distinction between the statistical concept of LD and the biological reality of haplotypes and their frequencies. The significant quantitative and qualitative variation in LD among populations, even for populations within a geographic region, emphasizes the importance of studying diverse populations in the HapMap project to assure broad applicability of the results.
Linkage disequilibrium is a nonrandom association of alleles at different loci (that is, you have two forms of two genes which show up together at higher than expected frequencies assuming random mating). Two genetically very distinct populations brought together and mated would give rise to offspring with a very high level of linkage disequilibrium in the initial hybrid generation, but in subsequent generations recombination should break apart the assocations between various alleles.
You can read the full paper here (PDF).
Posted by razib at 01:17 AM