Geneticists Identify Genes Behind What Makes You A 'Lark' Or An 'Owl'

Geneticists from the University of Leicester have identified the genetic clues behind what makes you a "lark" or an "owl" for the very first time. By carrying out their analysis on the fruit fly, they have discovered nearly 80 genes which can be associated with "morningness" and "eveningness." Study author Dr Eran Tauber says, "Most people find that their performance is at peak at specific times of day. A great variation in this diurnal preference is found, from early risers 'larks' to late night 'owls.' The impact of this preference ('chronotype') on health and behavior is well documented, but the molecular basis is largely unknown.”

The researchers of the study, published in the journal Frontiers in Neurology, used fruit-fly Drosophila, since their gene clocks are very similar to human, to get an first hand insight behind the "morningness/eveningness" preference on molecular level. Since the genetic makeup of insects and humans is very similar, they are positive that some of the genes that they have identified in flies would be also prove to play an important role in diurnal preference among humans.

Tauber explains that many people spent their maximum time indoors and thus are no longer exposed to the natural variations in light and temperature that characterises the day-night cycle. Also due to social and economical obligations, some people start their new day hours before the endogenous call from the body clock. Hence, the combined effect of these types of lifestyle cause major discrepancy between internal and external clock and can be pronounced for late rising "owl" or early rising "lark" chronotypes. Such dysfunctions in the clock reflect badly on the temporal disorientation and sleep problems and increase the risk of diseases such as obesity, mental illness, cardiovascular disease and cancer.

Tauber concluded by saying that "Looking at gene expression was only part of our research. An obvious question is what causes the different expression in the larks and owls. This difference is largely due to genetic variations in their DNA sequences --different gene versions that are present in larks and owls. In another set of experiments, we took advantage of the fact that the DNA sequence of the entire genome of many flies strains in now available. We carried a large survey and identified some interesting genetic variations that are associated with diurnal preference. We are currently analyzing the data and hope to publish the results in due course."

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