The vast majority of the human genome consists of DNA without any apparent function, so-called “junk DNA”. A study conducted by the scientists Dr. Laurence Ettwiller and Michael Eichenlaub at Heidelberg University's Centre for Organismal Studies now highlights this “dark matter” of the genome as a resource for evolutionary novelty.
The green fluorescent protein (GFP) labels in green the domains where the “de novo“ enhancers are active in the medaka fish (Oryzias latipes).
Image: Ettwiller / Eichenlaub
Japanese freshwater fish Medaka
Image: Ettwiller / Eichenlaub
The scientists found that even small changes in functionally inactive “junk DNA“ are sufficient to create essential control elements in gene regulation known as enhancers. The results of the study will be published on 1 November 2011 in “PLoS Biology”.
Genetic variation in humans is not primarily due to differences in the 1.5 percent of DNA that code for gene products. Rather, experts today assume that most differences between humans are the result of changes in those DNA sequences that control gene regulation, i.e. the formation of gene products such as proteins. Enhancers are an essential component in the control mechanism of gene regulation. Changes in enhancers can lead to disease and malformation; on the other hand, they carry the potential for evolutionary innovation.
Michael Eichenlaub and Laurence Ettwiller have shown that such innovation can occur through “de novo” formation of new enhancers, arising from slight changes in the DNA that had no regulatory activity before. This finding contrasts with the general view amongst evolutionary scientists that novelty mainly arises from modification of pre-existing functional components of the genome. This view has generally led scientists to focus their attention on the loss and modification of functional elements, neglecting variations in the “junk DNA“, which makes up about 97 percent of genetic information. “This work brings such neglected regions of the genome to the forefront as a putative ‘breeding ground‘ for new enhancers“, says Laurence Ettwiller, who headed the study.
To prove the existence of those new enhancers, the Heidelberg scientists designed an assay in the Japanese freshwater fish Medaka to capture rare events in which the sequence of a novel enhancer could be traced to other related species and validated these sequences experimentally. In several cases, they found evidence of a “de novo“ formation of new enhancers. “Even though this study has been conducted in fish, the same mechanisms apply to the human genome”, says Dr. Ettwiller.
“The study demonstrates that the slow but persistent changes that occur in DNA in each generation are sufficient to eventually lead to the apparition of new functions”, explains Michael Eichenlaub. “The methods we have established here could help to identify the changes that have contributed to the evolution of our species and explain the 1.23 percent of the genetic information that differ between the chimp’s and our genomes”, adds Dr. Ettwiller.
For more information, visit http://www.cos.uni-heidelberg.de/forschung/ettwiller/index.html.Original publication:
Marietta Fuhrmann-Koch | idw
The birth of a new protein
20.10.2017 | University of Arizona
Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research