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Five years ago, researchers using a new strategy in which they scanned large stretches of the genomes of the sick and the healthy turned up a common gene variant among those with the eye disease macular degeneration. The finding was remarkable: Relatively few people participated in the study, yet those with two copies of the suspect gene variant had 10 times the risk of macular degeneration, a huge increase. Almost immediately, researchers applied GWA to other conditions. But it quickly became clear that macular degeneration was an exception. Most GWA studies needed 10,000 or more volunteers to get a statistically significant result, because the effect of each gene was so small. Since the human genome was sequenced 10 years ago, technology has moved with lightning speed; many now believe that GWA methods, which cover a fraction of the genome, are becoming obsolete. Sequencing costs continue to plunge, and within a few years sequencing entire genomes of hundreds of subjects will be financially feasible. What has the GWA experience taught us? The results from one group of GWA studies, for heart disease, are typical, with a mixed record and an uncertain legacy.