Mice with deviant internal rhythms due to a genetic mutation have fewer offspring and shorter life spans than normal conspecifics whose rhythms follow the 24-hr cycle of a day more accurately. This discovery was made by a team of scientists led by researchers from the Max Planck Institute for Ornithology and Princeton University. Internal clocks that generate daily rhythms in living beings are among the most important achievements on earth. They are essential for coordinating processes of life with the environment. The study on mice shows that a deviation of internal rhythms from the 24-hr rotation of the earth has a direct influence on biological fitness.
Almost all living things possess internal clocks that govern periods of sleep and waking, and ensure that these processes are in synchrony with night and day. This circadian clock evolved to allow the anticipation of regular daily events.
Sunlight aligns the internal clock with the 24-hour-rhythm of the rotation of the earth. A fundamental, unanswered question so far has been: is the functioning of the internal clock important for how long an organism lives and how well it is able to reproduce in its natural environment?
Mutations in certain genes can disrupt the internal clock so that it runs out of sync with the day-night cycle. In mice, a mutation called tau is known to alter daily rhythms: mice carrying this mutation run through their day about two hours faster than normal mice.
Scientists from the Max Planck Institute for Ornithology in Seewiesen and Radolfzell together with colleagues from the University of Groningen, the University of Manchester and Princeton University studied the biological fitness of such mice with deviant circadian rhythms in a large outdoor enclosure for over a year, where they were exposed to natural predators.
At the beginning of the study the researchers divided 238 mice into six groups. For each group they housed an identical mix of mice without the mutation together with mice carrying either one or two copies of the mutation in their genes. Each mouse was equipped with a transponder, so that the scientists could monitor their activity rhythms at feeders. Mice with one or two copies of the mutation showed aberrant daily rhythms.
Mice without the mutation were observed to live longer and to produce more offspring than mice with the mutation that showed abnormal rhythms. As a consequence, after more than one year the prevalence of the mutation in the population dropped from an initial 50 percent in the starting population to only about 20 percent in the last cohort that was studied.
This finding led the researchers to conclude that strong selection pressures must exist against the tau mutation in a natural environment. “Our findings highlight the fundamental importance of circadian clocks for the biological fitness of living beings. This has never been shown that clearly”, summarizes senior author Michaela Hau. (SL/HR)
Prof. Dr. Michaela Hau
Max-Planck-Institut für Ornithologie
Abteilung Evolutionäre Physiologie
Tel. +49 (0) 8157 932-273
Dr. Kamiel Spoelstra
Netherlands Institute for Ecology, Wageningen
Department of Animal Ecology
Phone +31 (0)317 473 453
Dr. Sabine Spehn | Max-Planck-Institut für Ornithologie
Cloud Formation: How Feldspar Acts as Ice Nucleus
09.12.2016 | Karlsruher Institut für Technologie
Closing the carbon loop
08.12.2016 | University of Pittsburgh
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences