The findings suggest several potential targets for new genetic treatments. They also show how complicated the disease is: scientists now think we need to develop more personalised treatments and preventative measures.
The study explored the changes in DNA sequence that affect diabetes risk.
Researchers compared the genes of people who had type 2 diabetes and people who didn't. This let them test the effects of rare, or 'private', DNA differences as well as ones that are more common.
Most of the genetic risk of type 2 diabetes is a result of common differences in the genetic code, shared by many people. Each genetic difference causes a slight change in the risk of disease.
Some researchers had thought that genetic risk would depend on rare changes, unique to an individual and their relatives.
The finding will affect researchers' efforts to develop personalised treatment and prevention approaches. They will need to consider an individual's broader genetic profile, other risk factors and physical symptoms.
Mark McCarthy, from the Wellcome Trust Centre for Human Genetics at the University of Oxford, said: "In this study, we have been able to highlight, with unprecedented precision, a number of genes directly involved in the development of type 2 diabetes. These represent promising avenues for efforts to design new ways to treat or prevent the disease."