Genetic map can help to identify common deceases

Scientists have completed a world's first genetic "map" of human diversity, that will speed up the search for causes and cures for diseases ranging from Alzheimer's, asthma, cancer and diabetes, to heart disease. More than 200 researchers from six countries have spent three years deconstructing the human genome to discover the precise genetic differences between people.

The three-year, $138 million project scanned the DNA of 269 volunteers on three continents and found deep patterns in the seemingly random genetic variations that make one person different from another. Human DNA, they found, comes in distinct blocks, each of which can be identified by looking at only a few locations, the way a person might be able to identify a familiar quilt by examining just a handful of its cloth panels. This will greatly reduce the number of the 3 billion units of human DNA that must be checked, and allow scientists to find elusive genetic variations that cause disease, Boston Globe reports.

The human genome - the basic genetic blueprint - showed that any two people shares 99.9 per cent of their genes, it is the 0.1 per cent difference that holds the key to why some of us are more susceptible to common diseases such as diabetes and hypertension or respond differently to drugs.

The scientists built up the map of genetic diversity from a detailed analysis of the DNA from 269 volunteers drawn from four different ethnic groups - the Yoruba tribe from Nigeria, residents of Tokyo, the Han Chinese from Beijing and European Americans from Utah, China View reports.

Scientists have called the study "HapMap" because it is based on these human haplotypes. More than a million single mutations have so far been mapped to their respective haplotypes.

Using HapMap, researchers can compare genetic patterns of people affected by a disease with those who are unaffected. The researchers estimated that the study will increase by 20-fold the speed at which it is possible to search for the genes responsible for disease. A.M.