The human genome is 3.5 billion DNA letters long. At the genetic level, any two individual is about 99.5% alike. This means that there is a spelling difference every thousand bases or so. The way we read out these differences is with DNA chips. In the course of an hour, over one million of these sites of differences can be read using microarray technology. This visualization, a part of the DataStream exhibit at the DNAtrium, shows actual data from Genetic Analysis platform at the Broad Institute. The data being shown are from people infected with HIV but do not develop AIDS. By looking at the genetic underpinnings of these individuals, researchers hope to understand the mechanism of HIV "resistance." The displays shows the variation being read and then mapped to its corresponding location in the genome.