HapMap scientists provide detailed plans 19/12/03. By the Wellcome Trust Sanger Institute The international team of scientists working to determine the most common variations of the human genome reported the details of their plans, known as the HapMap Project, in the 18 December 2003 issue of the journal Nature.

The team will obtain and identify genetic variations in DNA samples from 270 people in Nigeria, Japan, China and the USA. Once finished, the HapMap will provide a freely available catalogue of common patterns, or haplotypes.

Our individual predisposition to disease and our response to medicines are, in part, encoded within our DNA, in the differences (called single-nucleotide polymorphisms, or SNPs) scattered through our genetic sequence. However, we tend to share regions of SNPs with others, and these regions can be mapped onto the reference genome sequence.

Importantly, many regions can be 'tagged' by identifying SNPs that are characteristic of the region. The HapMap Project will define those all-important 'tag' SNPs in multiple populations and the regions of the genome where they are located.

As a result of the HapMap Project, researchers will not have to search through the 10 000 000 SNPs that occur in the human genome, but instead will be able to use the map developed by the Project to obtain as much information using a massively reduced number of SNPs, about 500 000.

Feature: The International HapMap Project

Ninety samples from the Yoruba people in Ibadan, Nigeria, will be analysed, along with 90 from people of Northern and Western European ancestry living in Utah. While the Nigerian and US samples will be from 30 'trios' - sets of parents and an adult child - 45 samples from Japanese and 45 samples from Han Chinese will be from unrelated people.

Feature: Haplotype mapping ethics

Image credit: Neil Leslie