That 0.1% difference in DNA makes all the difference

THE first genetic "map" of human diversity was published yesterday by scientists who described it as a landmark achievement that would revolutionise medicine, reported The Independent..More than 200 researchers from six countries have spent three years and around $250 million deconstructing the human genome to discover the precise genetic differences between people..Whereas the human genome — the basic genetic blueprint — shows that 99.9 per cent of genes are shared by everyone, it is the 0.1 per cent difference that can hold clues to illnesses such as asthma, diabetes, dementia, heart disease and cancer..Scientists have completed the first phase of an ambitious project to tease apart these minute differences to try to explain why some people develop serious diseases while others with a similar lifestyle remain healthy..The map of human diversity could also be used to identify patients who respond better to certain drugs, as well as explaining the evolutionary origins of humankind by shedding light on the ancient migrations of our ancestors from Africa.."This represents a milestone for medical research," said Dr David Altshuler of Harvard University, one of the leaders of the team to draw up the genetic map, published in the journal Nature. He said that the map provides a powerful new tool for exploring the root causes of the many common diseases that have a genetic as well as lifestyle component..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..By painstakingly comparing the smallest possible mutations in each of the volunteer's DNA, the scientists produced the first comprehensive catalogue of human genetic variation..Dr Panos Deloukas, a senior investigator at the Wellcome Trust Sanger Institute in Cambridge, said that a map of such differences will ultimately prove invaluable in understanding the many life-threatening diseases affecting people today.."Humans are genetically 99.9-per-cent identical. It is the tiny percentage that is different 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," Dr Deloukas said..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.."This report describes a remarkable step in our journey to understand human biology and disease," said Prof Peter Donnelly of Oxford University, a senior member of the research team..The study — which was funded by governments and private industry — is available at www.nature.com..The human genome is like a recipe for making a man or woman and is composed of three billion individual "letters" that make up the long genetic code written within our genes..When the full sequence or map of the human genome was published it was clear that 99.9 per cent of the code was identical for all people of any ethnic group in the world..But the 0.1 per cent of the code that is different not only accounts for why people look dissimilar — it can also explain why each of us can have different destinies in health.