Description: In the largest study to date of the genetics of diseases, researchers say they've substantially increased the number of genes believed to play a role in the development of common illnesses, ranging from bipolar disorder to diabetes.

Many of these genes were found in areas of the human genome not previously thought to be related to the diseases, the researchers said. While much was already known about genetic-based diseases, such as cystic fibrosis, little was known about the genetic components of more common diseases.

"These are like heart disease, schizophrenia, depression and arthritis, where we have known that genetics plays a role, but we haven't been able to pinpoint the genetic factors which are involved," said lead researcher Peter Donnelly, of the Department of Statistics at the University of Oxford in England. "Our study is a new dawn to understanding genetic components of common diseases.

"For most common human disease, despite h