Differences of linkage disequilibrium structure. HapMap based LD around SNP rs629301, near SORT1 (denoted by arrow), in (a) Europeans (CEU) and (b) West Africans (YRI) that associated with low density lipoprotein in both Europeans and African Americans. For this SNP, the region of linkage disequilibrium around it narrowed in the African population to 468 bp from approximately 16 kb in the European population, as indicated by red and yellow diamonds, providing a 30-fold reduction in the associating region. bp, base pair; kb, kilobase; LD, linkage disequilibrium; SNP, single nucleotide polymorphism. (From ).