UK researchers are to analyse thousands of DNA samples in a bid to find genetic signposts for eight major diseases.
Scientists will look at key areas where people's DNA differs
The collaboration of 24 leading human geneticists, is to receive £9m in funding from the Wellcome Trust.
They will look at TB, heart disease, type 1 and 2 diabetes, arthritis, Crohn's disease, ulcerative colitis, bipolar disorder and hypertension.
It is hoped the project will lead to better understanding of who is at risk, and the development of new treatments.
Researchers in the Wellcome Trust Case Control Consortium (WTCCC) will analyse over 19,000 DNA samples - 2,000 from patients with each disease which will be compared with 3,000 samples from healthy people to identify the genetic differences between them.
Work will take place at centres throughout the UK including the Wellcome Trust Sanger Institute, Cambridge University and Oxford University.
Although the human genome is made up of more than three billion chemical bases, researchers now know that most of these are identical in everyone.
This project will examine 675,000 points where key variations occur.
Professor Peter Donnelly from the Department of Statistics at Oxford University, who chairs the consortium, explained: "To treat a disease effectively, we need to understand it.
"If we can identify the common genetic triggers for these diseases, it will give us a foothold in the biological cycle and leave us better situated to fully understand what happens with each of these diseases and who may be more likely to get them."
He added: "This should open the door for us to develop better diagnostic tests and also help in developing more effective treatments."
"A single disease has never been subject to such level of intense genetic analysis.
"The fact that we're looking at eight underlines the significance of this programme and the progress being made in this field."
Dr Mark Walport, Director of the Wellcome Trust, said: "This groundbreaking project is possible because of the sequencing of the human genome.
"Hopefully, with the insight gained into these diseases we will be able to make real progress in combating them."
In second project, the WTCCC will analyse 15,000 positions where key variations occur to look for genetic variations relating to another four diseases - breast cancer, autoimmune thyroid disease, multiple sclerosis and ankylosing spondylitis.