An international team of 200 scientists mapped the entire genome of 269 people, and identified tiny differences in key areas of DNA. The HapMAp is a map of the most common differences in the human genome, which could lead to personalised treatments for diseases.

Humans are genetically 99.9% identical, but the remaining 0.1% accounts for important differences between people. Much of the genetic variation between individuals is caused by single letter differences in DNA called single-nucleotide polymorphisms (SNPs).
They are grouped into inherited families called "haplotypes", which are combinations of minute variations in DNA that have travelled together over evolutionary time. There are thought to be around 10 million SNPs.
HapMAp looked at people from Africa, the Far East and western Europe and identified 300,000 SNPs which can provide around 90% of the information obtained by looking at all 10 million.

HapMap data is already being used by scientists to detect a genetic defect that substantially increases the risk of age-related macular degeneration, the leading cause of impaired vision in the elderly and other conditions including diabetes, Alzheimer's disease, cancer, schizophrenia, asthma, high blood pressure and heart disease.

Scientists who were involved in the study say that HapMap is a huge step toward the understanding of human biology and disease.

However, there are scientists that are not as enthusiastic about the HapMAp as it tells only "half the story" and it could not be used for rare diseases. Although they admit it will save a huge amount of time for researchers, it is still not a panacea.