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
Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System
Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences