A team of biologists from Indiana University and Brown University believes it has discovered the mechanism by which interacting mutations in mitochondrial and nuclear DNA produce an incompatible genotype that reduces reproductive fitness and delays development in fruit flies.
The new research, led by IU biologists Kristi Montooth and Colin Meiklejohn and including former IU undergraduate researcher Mo Siddiq, describes the cause and consequences of an interaction between the two genomes that co-exist within eukaryotic cells. Animal mitochondrial DNA, or mtDNA, is a small but important genome that encodes a handful of proteins that are essential to oxidative phosphorylation, the pathway that produces the adenosine triphosphate molecule that fuels cellular metabolism.
With this new characterization of a disruptive interaction between mtDNA and nuclear DNA mutations, the scientists provide one of the few mapped cases of a fitness-reducing mitochondrial-nuclear incompatibility.
The genetic interaction that IU biologists mapped, in collaboration with Brown University biologist David Rand, is between mutations that are present in natural populations, rather than being induced in the lab. This has important consequences for understanding genetically complex human diseases.
Many human diseases, such as neuromuscular and neurodegenerative disorders, are associated with mutations in mitochondrial transfer RNAs, or tRNAs, but a single mutation can be highly variable in the degree to which it leads to disease.
Montooth and her colleagues' findings suggest that the combined mitochondrial-nuclear genotype for tRNAs and their tRNA synthetases may, in fact, be a better predictor of disease.
"Interactions between mitochondrial and nuclear DNA for fitness have been documented in many organisms, but rarely has the genetic or mechanistic basis of these interactions been elucidated," said Montooth, an assistant professor in the IU College of Arts and Sciences' Department of Biology. "This has limited our understanding of which genes harbor variants causing mitochondrial-nuclear disruption and the processes that are impacted by the co-evolution of these genomes."
Using genetic techniques and many resources available from IU's own Bloomington Drosophila Stock Center, the scientists mapped an interaction between a single mutation in a mitochondrial tRNA gene, mt-tRNA-Tyr, and an amino acid change in its nuclear-encoded charging enzyme, the mitochondrially targeted amino acyl tRNA synthetase, mt-TyrRS -- the enzyme that places the proper amino acid on the tRNA to allow for mitochondrial protein synthesis.
"As a result, the incompatibility decreases the activity of the oxidative phosphorylation pathway," Montooth said, "demonstrating that decreased mitochondrial protein synthesis compromises the energetic function required for proper development of adult structures, such as the ovary and sensory bristles."
These types of fitness-reducing genetic incompatibilities are one hypothesized mechanism that can maintain the formation of new species.
The new research, "An Incompatibility Between a Mitochondrial tRNA and Its Nuclear-Encoded tRNA Synthetase Compromises Development and Fitness in Drosophila," was published online Jan. 31 in PLOS Genetics. Additional co-authors with Montooth, Meiklejohn, Siddiq and Rand were Marissa A. Holmbeck and Dawn N. Abt, both of Brown.
This research was funded by the National Institutes of Health, the National Science Foundation, IU and the IU Hutton Honors College.
Steve Chaplin | EurekAlert!
New mechanisms uncovered explaining frost tolerance in plants
26.09.2016 | Technische Universität München
Chains of nanogold – forged with atomic precision
23.09.2016 | Suomen Akatemia (Academy of Finland)
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.
Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...
At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.
In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...
Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.
K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...
23.09.2016 | Event News
20.09.2016 | Event News
16.09.2016 | Event News
26.09.2016 | Materials Sciences
26.09.2016 | Materials Sciences
26.09.2016 | Materials Sciences