The findings, just published in the journal PLoS One, are a biological oddity previously unknown in animals. But they may also provide an important new tool to study human aging, scientists said. The work was supported by the National Institutes of Health.
Courtesy of Oregon State University
For the first time researchers have found "selfish DNA" in the mitochondria of an animal, this roundworm, Caenorhabditis briggsae .
Such selfish mitochondrial DNA has been found before in plants, but not animals. In this case, the discovery was made almost by accident during some genetic research being done on a nematode, Caenorhabditis briggsae – a type of small roundworm.
“We weren’t even looking for this when we found it, at first we thought it must be a laboratory error,” said Dee Denver, an OSU associate professor of zoology. “Selfish DNA is not supposed to be found in animals. But it could turn out to be fairly important as a new genetic model to study the type of mitochondrial decay that is associated with human aging.”
DNA is the material that holds the basic genetic code for living organisms, and through complex biological processes guides beneficial cellular functions. Some of it is also found in the mitochondria, or energy-producing “powerhouse” of cells, which at one point in evolution was separate from the other DNA.
The mitochondria generally act for the benefit of the cell, even though it is somewhat separate. But the “selfish” DNA found in some plant mitochondria – and now in animals – has major differences. It tends to copy itself faster than other DNA, has no function useful to the cell, and in some cases actually harms the cell. In plants, for instance, it can affect flowering and sometimes cause sterility.
“We had seen this DNA before in this nematode and knew it was harmful, but didn’t realize it was selfish,” said Katie Clark, an OSU postdoctoral fellow. “Worms with it had less offspring than those without, they had less muscle activity. It might suggest that natural selection doesn’t work very well in this species.”
That’s part of the general quandary of selfish DNA in general, the scientists said. If it doesn’t help the organism survive and reproduce, why hasn’t it disappeared as a result of evolutionary pressure? Its persistence, they say, is an example of how natural selection doesn’t always work, either at the organism or cellular level. Biological progress is not perfect.
In this case, the population sizes of the nematode may be too small to eliminate the selfish DNA, researchers said.
What’s also interesting, they say, is that the defects this selfish DNA cause in this roundworm are surprisingly similar to the decayed mitochondrial DNA that accumulates as one aspect of human aging. More of the selfish DNA is also found in the worms as they age.
Further study of these biological differences may help shed light on what can cause the mitochondrial dysfunction, Denver said, and give researchers a new tool with which to study the aging process.
Dee Denver | Newswise Science News
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
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,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy