power as densities of genomic markers increase. Association identifies much smaller chromosomal regions than linkage-based approaches. Association thus allows us to identify variants in specific genes rather than in large chromosomal regions. Genome wide association fosters pooling strategies that preserve confidentiality and reduce costs, as we discuss below [10–12, 33, 38–44]. Genome wide association provides ample genomic controls. Proper genomic controls can minimize the chances that disease vs control differences are confounded by occult stratification, such as the stratification that might arise from unintended occult ethnic mismatches between disease and control samples.
