Consortium Completes HapMap

Phase I of a new tool called HapMap, which will speed the discovery of genes for common diseases, has been completed by more than 200 researchers from Canada, China, Japan, Nigeria, the United Kingdom, and the United States.

The results, reported in the October 27, 2005, issue of Nature, provide overwhelming evidence that variation in the human genome is organized into local neighborhoods, called haplotypes, which are usually inherited as intact blocks of information. The HapMap consists of more than one million markers of genetic variation, or single nucleotide polymorphisms (SNPs). The same group is nearing completion of the Phase II HapMap, which will contain nearly three times more markers than the initial version.

The International HapMap Consortium (Salt Lake City, UT, USA; www.hapmap.org) produced the HapMap using DNA from blood samples collected from 269 volunteers from widely distributed geographical regions. Specifically, the samples came from Yoruba residents in Ibadan, Nigeria; Japanese residents in Tokyo, Japan; Han Chinese residents in Beijing, China; and Utah (USA) residents with ancestry from northern and western Europe.

Genetic diversity in humans is increased by recombination, which is the swapping of DNA from the maternal and paternal lines. By analyzing the HapMap data, researchers have produced a genome-wide inventory of where recombination takes place. The HapMap shows neighborhoods of correlated genetic variation, or haplotypes, across the entire human genome.

"The HapMap is a phenomenal tool that is making possible research that was impractical, if not unimaginable, only a few years ago,” said Yusuke Nakamura, M.D., Ph.D., director of the University of Tokyo's Human Genome Center who also worked on the HapMap. "It offers the scientific community an enormous savings, reducing the expense of searching the genome for hereditary factors in common disease by a factor of 10 to 20.”






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