Medical applications of haplotype-based SNP maps: learning to walk before we run

Ever since Risch and Merikangas1 introduced the concept of whole-genome association using single-nucleotide polymorphisms (SNPs) in 1996, the question of how many SNPs would be required for whole-genome association studies has been extensively debated2, 3. The initial prediction of one million SNPs has recently been reduced to approximately 300,000 (ref.