Beyond the HapMap Genotypic Data: Prospects of Deep Resequencing Projects

The International HapMap Project provides a key resource of genotypic data on human samples including lymphoblastoid cell lines derived from individuals of four major world populations of African, European, Japanese and Chinese ancestry. Researchers have utilized this resource to identify genetic elements that correlate with various phenotypes such as risks of common diseases, individual drug response and gene expression variation. However, recent comparative studies have suggested that the currently available HapMap genotypic data may not capture a substantial proportion of rare or untyped SNPs in these populations, implying that the HapMap SNPs may not be sufficient for comprehensive association studies. In this paper, three large-scale deep resequencing projects covering the HapMap samples: ENCODE (Encyclopedia of DNA Elements), SeattleSNPs and NIEHS (National Institute of Environmental Health Sciences) Environmental Genome Project are discussed. Prospectively, once integrated with the HapMap resource, these efforts will greatly benefit the next wave of association studies and data mining using these cell lines.