There are two types of people in this world: those who do their best work first thing in the morning just after the sun drags itself out of bed, and those who can only operate at night when the people who host late-night TV infomercials for hair-in-a-can and miracle towels are telling their audience they really need to get some sleep.
But what exactly makes us morning or night people? The answer might lie in our genetic makeup.
Geneticists from the University of Leicester may have cracked the early-bird and night-owl mystery by identifying genes in fruit flies that seem to be associated with a preference for morning or evening activity, according to a release May 14.
The researchers identified types of flies that tended to emerge from their pupal cases in the morning or the evening, and examined their RNA, according to the release, eventually finding "nearly 80 genes that show substantial difference in their expression" and that may influence whether a fly prefers day or evening.
"Because this genetic system is so similar between insects and human, there is a good chance that some of the genes we have identified in flies would be also important for diurnal preference in humans," said researcher Eran Tauber, a co-author on the paper. The findings were published May 8 in the journal Frontiers of Neurology.
"A key finding of this study was that most of the genes that we identified are not core-clock genes but genes involved in a diverse range of molecular pathways," lead investigator Ezio Rosato said. "This changes our view of the body clock from a pacemaker that drives rhythms to a time reference system that interacts with the environment."
That interaction between the body clock and the environment can get dysfunctional, though. We humans are often required to get up and be active at times that aren't in sync with our natural rhythms, a conflict that Tauber said is implicated in not just "temporal disorientation and sleep problems, but also in conditions such as obesity, mental illness, cardiovascular disease and cancer." Tauber suggested that the team's research could forward development of ways to help people deal with this type of body clock conflict based on whether they're naturally night or morning people.
Sleep patterns may be tied to health in multiple ways. A study written up in 2014 in the medical journal Molecular Psychiatry concluded that genes may also affect our sleep patterns and sleep quality. The study monitored the sleep patterns and genes of more than 50,000 people and found two genetic variations linked to sleep duration. According to the study, the people who tended to sleep slightly longer were more likely to have lower blood sugar levels and less likely to have attention deficit hyperactivity disorder (ADHD).
Hopefully, this type of research will eventually lead to new treatments for mental and physical health conditions, and maybe even a new strain of coffee that can wake us up on a molecular level.