A Salk Institute study found that the activity of nearly 80 percent of genes follows a day/night rhythm in many tissue types and brain regions, reports Technology Networks.

While scientists have long known that many tissues follow these cycles, called circadian rhythms, this is the most comprehensive study connecting timing to gene transcription (the process of copying DNA into RNA to guide protein assembly).

“This is the first time a reference map of daily gene expression has been established,” says Satchidananda Panda, a professor in Salk’s Regulatory Biology Laboratory and senior author on the paper. “It’s a framework to understand how circadian disruption causes diseases of the brain and body, such as depression, Crohn’s disease, IBD, heart disease or cancer. This will have huge impact on understanding the mechanisms or optimizing cures for at least 150 diseases.”