The circadian clock, along with the rhythms it produces, is very essential for human health but it is often disturbed by external factors in the modern environment. A researcher has developed a computer method that predicts an individual's "internal" time of the day, which could help to identify and analyze circadian disorders and sleep-related problems so that a personalized treatment can be prescribed.

The method, called ZeitZeiger, analyzes blood samples to accurately predict the circadian time of an individual. Jacob Hughey of the Department of Biomedical Informatics at the Vanderbilt University School of Medicine developed the method.

How Was ZeitZeiger Developed?

Hughey and his team of researchers used 15 genes to see if circadian time could be predicted. However, the output of the study surprised them. According to the results, 13 of 15 selected genes were found to be non-core genes belonging to the human circadian clock.

In order to generate and regulate circadian rhythms it is necessary to find core genes. Hughey compared the core genes to the gears of a clock, which one requires to check the accurate time.

"Most of the genes that were selected for ZeitZeiger seem to be outputs of the clock; that is they are not the gears controlling the clock, but the hands telling the time," said Hughey.

Thus it was concluded that data from almost every gene, even if it's not the core gene, present in the genome has to be collected to figure out which genes will provide the most correct predictions.

How Was ZeitZeiger Trained?

ZeitZeiger was trained to analyze how the circadian clock gets disturbed by sleep and light-dark cycles. Hughey and his fellow researchers used 498 publicly available blood samples from 60 individuals to train the computer method. They analyzed the RNA in the samples using the machine learning algorithm. Through ZeitZeiger, they were able to spot a set of genes that could accurately predict an individual's circadian time.

The group of researchers also highlighted how ZeitZeiger can be helpful in showing how disturbances in a person's light-dark and sleep-wake cycles can affect their circadian clock.

One of the main reasons for the disruption of the circadian rhythm is the negative impact of the modern environment on sleep, mostly due to lack of proper sunlight and shift work. This disruption may also cause cancer, depression, and obesity.

The research has been published in the journal Genome Medicine.

Photo: National Human Genome Research Institute | Flickr