A major scientific step in the field of genetics is set to speed up the search for the causes of common illnesses ranging from heart disease and cancer to Alzheimer's and asthma.
They have completed a map that charts patterns of human genetic variation in the world population, to better understand human biology, evolution and how to diagnose diseases.
"It is a scientific milestone because it now links directly to the human genome sequence and provides a tool to streamline genetic studies," said Dr Panos Deloukas, of the Wellcome Trust Sanger Institute.
The Human Genome Project, which mapped the three billion letters that make up the human genetic code, showed that any two people are 99.9 percent the same.
Now an international consortium of scientists has completed a more detailed chart, or HapMap, showing markers of genetic variation, or single nucleotide polymorphisms (SNPs), to explain the 0.1 percent difference.
The HapMap shows SNPs are grouped in neighborhoods, or haplotypes, and are usually inherited as blocks of information.
The International HapMap Consortium, a public-private partnership of 200 scientists from Britain, the United States, Canada, Japan, Nigeria and China developed the HapMap using DNA samples from 269 people from Asia, Africa and the United States.
"The human genome sequence provided us with the list of many of the parts to make a human. The HapMap provides us with indicators - like Post-It notes - which we can focus on in looking for genes involved in common diseases," said Professor Peter Donnelly, of Oxford University in England.
Using the HapMap, scientists can compare SNP patterns in people with an illness to healthy individuals to identify its underlying genetic causes, Reuters reports.