Sleep behavior is recognizable by the hair. An analysis of individual genes shows whether people are early risers or late risers, for example.
(08/24/2010) Does the internal clock tick in hair? Not quite, but people's sleep behavior can also be identified by analyzing individual genes in their hair. Japanese scientists came to this result in a series of experiments. The researchers hope that the study results will provide more insights into the treatment of sleep problems and sleep disorders. Such so-called clock genes have been known to research for more than ten years. It has also been known for a long time that an ongoing disturbance of the internal clock leads to illnesses.
Scientists headed by study leader Makoto Akashi from the Japanese University of Yamaguchi examined so-called watch genes in hair follicles that play a role in the control of human internal clocks. The researchers found that the earliest activity of the individual genes can also be detected in the subjects who wake up early. For workers and employees who work in weekly shift shifts, the phases in which the watch genes are read in relation to waking phases were shifted on average by 5 hours.
The internal clock controlled by clock genes has been scientifically proven for more than ten years. The internal clock specifies the functions and the rhythm of the organs. The biological clock of humans regulates, among other things. the storage of energy and its utilization in a "cyclical rhythm". The human organism is oriented among other things to external circumstances such as day and night. The "internal clock" is regulated in the brain by the "suprachiasmatic nucleus". Most people know of a disturbance of the internal clock due to a "jet lag". This leads to the organs being activated at the "wrong time" if there are serious differences in time. This in turn leads to symptoms and complaints. Such "clocks" exist not only in the brain, but also in other parts of the human body. Biological clocks exist in the brain, liver, lungs, heart, kidneys and in the pancreas.
Shift workers are particularly affected by a clock disturbance. Here the clock changes almost weekly. If the body has just settled to the new rhythm, it will have to reorient itself the next time the shift changes. Shift workers therefore have an increased risk of illness. In industrialized countries, the internal clock is getting out of step. Artificial light in offices, for example, causes day and night sensations to be disturbed.
During the course of the study, the scientists collected hair from a total of four subjects every three hours. They removed hair from the main hair and the whiskers. The study participants had previously been adjusted to a regular daily rhythm. If the participants had thick hair, five hairs were sufficient to clearly measure the activity of the genes. For those who had fine hair, at least 20 hairs were necessary. Until now, scientists had in skin cells that were taken during a biopsy.
However, the study primarily focused on shift workers. The same series of experiments was also used for shift workers who work alternately in the early shift and in the late shift. But the activities of the genes during the day in these subjects were very changeable and unstructured. One of the genes, the Per3 gene, was most active in the study participants with a regular rhythm about an hour before waking up. In the shift workers who work the early shift, the gene was most active only one hour after getting up.
Shift work is therefore hazardous to health. Shift workers suffer excessively from sleep disorders, metabolic disorders, diabetes, cardiovascular diseases and cancer. But a general statement that all shift workers are affected equally cannot be made. The body of the individual develops different tolerances. Many "inner clocks" adapt well to different lifestyles, others not at all. Why this is so different can still not be clearly said. (sb)
In: PNAS 10.1073 / pnas.1003878107, 2010. and
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