There Are Genetic Differences Between Early Risers and Night Owls

Whether or not you’re a morning person may be encoded in your DNA. A team of geneticists from the University of Leicester has identified almost 80 genes in flies that seem to be associated with different circadian rhythms, as they explain in a study published in the journal Frontiers in Neurology.

Fruit flies are often used as model organisms in genetic research because a large portion of their genetic material can also be found in humans. Flies emerge from their pupal case at different times based on their internal clock, with some types of fruit flies making the transition to adulthood at dawn (so-called "larks"), and others late at night ("owls"). Looking at the gene expression of these early risers and night owls, the geneticists were able to pinpoint significant differences in the genetic systems of the two groups, as you can see in this diagram: 

Gene expression levels during the day in fruit flies. Purple represents expression levels above the mean, green below the mean. Image Credit: University of Leicester

Most of the gene expressions that differed between the two groups of flies did not have anything to do with the clock genes that have previously been linked to circadian rhythms. Study author Eran Tauber explains the phenomenon as a kind of pinball machine. 

“Once a gene expression is delayed (in Larks), a completely different cascade of molecular events is carried, similar to the ball in a pinball machine that takes a different route in each run,” he says in a press statement. “The end point might be similar, but the different molecular routes result in a different journey time."

Identifying which genes are involved in the process of regulating the body’s internal clock could one day lead to better treatment for dysfunctional circadian systems, which not only cause sleep issues but have also been implicated in obesity, cancer, and psychiatric disorders.