Launched in 2002, the International HapMap Project was a collaborative effort among scientists from around the world to create a map of common patterns of genetic variation in the human genome. HapMap stands for haplotype map. A haplotype is a stretch of DNA nucleotides, or letters, that individuals inherit as a block because they lie relatively close together along a chromosome. For any particular region of a chromosome, there may be multiple different haplotypes present among humans, each characterized by a slightly different DNA sequence. By collecting and sequencing the DNA of initially 270 individuals from several different geographic regions, HapMap scientists were able to identify common haplotypes that exist among those individuals, as well as reliable markers to distinguish them. That collection of haplotypes and identifying markers—the HapMap—provided a shortcut for researchers who wanted to identify associations between those inherited DNA variants and particular human traits, especially common, complex diseases like heart disease and cancer.