8. Genome-wide association studies
Linkage studies are extremely attractive tools in human genetics but they can only identify highly penetrant loci and have been notably successful in the identification of monogenic forms of hypertension, The recent developments in genotyping technology with the introduction of chip-based genotyping arrays [84] and [85] has paved the way for GWAS that genotype for a large number of genetic markers usually SNPs (for example about 500,000 in the Wellcome Trust Case Control Consortium (WTCCC) study [78]) as opposed to the highly polymorphic microsatellite markers that have been used in classic genome-wide linkage studies. With the resources from Hapmap, it is possible to impute up to 2.5 million SNPs in LD with the tag SNPs present in these GWAS SNP arrays.