Newly discovered DNA sequences can protect chromosomes in rotifersJune 05, 2017
WOODS HOLE, Mass. -- Rotifers are tough, microscopic organisms highly resistant to radiation and repeated cycles of dehydration and rehydration. Now Irina Arkhipova, Irina Yushenova, and Fernando Rodriguez of the Marine Biological Laboratory (MBL) have discovered another protective mechanism of this hardy organism: the Terminons. Their findings, which can have implications for research on aging and genome evolution, are published this week in Molecular Biology and Evolution.
Terminons are a type of retrotransposon, DNA sequences that can copy themselves from RNA and relocate within the genome. While most transposons insert between DNA sequences, Terminons are unusual in that they attach at the end of chromosomes. Arkhipova first came across transposable elements that insert at chromosome ends in 2007 but only now has the size of these transposons been determined.
Chromosomes in eukaryotic cells (which make up all multicellular organisms) are capped with DNA sequences called telomeres, which protect the ends from degradation. By attaching to telomeres, Terminons provide even more buffer against chromosome degradation, which has been associated with aging. The discovery of Terminons could have substantial impact for research on the mechanisms of aging.
The Terminon is a giant transposon, approximately six times the size of the typical retrotransposon. Terminons reach this giant size because they seem to pick up additional genes, either from viral or cellular origins, Arkhipova says. While Terminons may be involved in capturing foreign genes -- a highly unusual property of bdelloid rotifers discovered in Arkhipova's lab -- it is unclear how this happens. Depending on what genes they acquire, some retrotransposons have evolved into viruses. So could Terminons evolve into viruses?
"That would be a very interesting question we hope to address, but these would be totally new types of viruses that haven't been described before," Arkhipova says.
Absent from all other life forms, Terminons are found in only the bdelloid rotifers. Members of this rotifer class span tens of millions of years of evolutionary history, suggesting this protective mechanism for their chromosomes is ancient. With so many undiscovered organisms occupying every niche of our globe, it is possible there are other unknown types of transposable elements that have potential for tremendous impacts on their hosts.
Several MBL scientists are actively developing the rotifer as a model system to study transposable elements in the genome, the mechanisms of aging, DNA repair strategies, and evolution without sexual reproduction.
Arkhipova, I., Yushenova, I.A., and Rodriguez, F. (2017) Giant reverse transcriptase-encoding transposable elements at telomeres. Mol. Biol. Evol. DOI: 10.1093/molbev/msx159
The Marine Biological Laboratory (MBL) is dedicated to scientific discovery - exploring fundamental biology, understanding marine biodiversity and the environment, and informing the human condition through research and education. Founded in Woods Hole, Massachusetts in 1888, the MBL is a private, nonprofit institution and an affiliate of the University of Chicago.
Marine Biological Laboratory
Related Evolution Articles:
The evolution of cells and organisms is thought to have been preceded by a phase in which informational molecules like DNA could be replicated selectively.
A new study by University of Arizona biologists helps explain why different groups of animals differ dramatically in their number of species, and how this is related to differences in their body forms and ways of life.
A genome project, comprising six evolutionary biologists from Professor Axel Meyer's research team from Konstanz and researchers from China and Singapore, sequenced and analyzed the genome of the tiger tail seahorse.
Rapid evolution of other species happens all around us all the time -- and many of the most extreme examples are associated with human influences.
Landscapes are formed by a combination of uplift and erosion.
How enzymes -- the biological proteins that act as catalysts and help complex reactions occur -- are 'tuned' to work at a particular temperature is described in new research from groups in New Zealand and the UK, including the University of Bristol.
On Nov. 11, 1954, Syuiti Mori turned out the lights on a small group of fruit flies.
A team of researchers, among them a zoologist from the University of Cologne, has succeeded in reconstructing a 160 million year old compound eye of a fossil crustacean found in southeastern France visible.
Evolution may be more intelligent than we thought, according to a University of Southampton professor.
Organized opposition to the teaching of evolution in public schoolsin the United States began in the 1920s, leading to the famous Scopes Monkey trial.
Related Evolution Reading:
Why Evolution Is True
by Jerry A. Coyne (Author)
"Coyne's knowledge of evolutionary biology is prodigious, his deployment of it as masterful as his touch is light." -Richard Dawkins
In the current debate about creationism and intelligent design, there is an element of the controversy that is rarely mentioned-the evidence. Yet the proof of evolution by natural selection is vast, varied, and magnificent. In this succinct and accessible summary of the facts supporting the theory of natural selection, Jerry A. Coyne dispels common misunderstandings and fears about evolution and clearly confirms the scientific truth that... View Details
Evolution: A Visual Record
by Robert Clark (Author)
Stunning images to reawaken us to the scientific process that drives the amazing diversity of life on earth
Evidence of evolution is everywhere. Through 200 revelatory images, award-winning photographer Robert Clark makes one of the most important foundations of science clear and exciting to everyone. Evolution: A Visual Record transports readers from the near-mystical(human ancestors) to the historic (the famous 'finches' Darwin collected on the Galapagos Islands that spurred his theory); the recently understood (the link between dinosaurs and modern birds)... View Details
Evolution: The Cutting-Edge Guide to Breaking Down Mental Walls and Building the Body You've Always Wanted
by Joe Manganiello (Author)
Joe Manganiello first gained recognition around the world for his incredible, sculpted body while winning both popular and critical praise as the star of HBO's True Blood. Now, from the man that Magic Mike director Steven Soderbergh called “walking CGI,” comes the cutting-edge guide to achieving the perfect body and therefore enhancing your overall quality of life.
With a build that men envy and women adore, Joe Manganiello is more than qualified to write the end-all guide to sculpting the perfect body. His fit physique catapulted him to the top of the list of... View Details
Evolution: Making Sense of Life
by Carl Zimmer (Author), Douglas J. Emlen (Author)
Science writer Carl Zimmer and evolutionary biologist Douglas Emlen have produced a thoroughly revised new edition of their widely praised evolution textbook. Emlen, an award-winning evolutionary biologist at the University of Montana, has infused Evolution: Making Sense of Life with the technical rigor and conceptual depth that today’s biology majors require. Zimmer, an award-winning New York Times columnist, brings compelling storytelling to the book, bringing evolutionary research to life. Students will learn the fundamental concepts of evolutionary theory, such as natural... View Details
by Douglas J. Futuyma (Author), Mark Kirkpatrick (Author)
Extensively rewritten and reorganized, this new edition of Evolution--featuring a new coauthor: Mark Kirkpatrick (The University of Texas at Austin)--offers additional expertise in evolutionary genetics and genomics, the fastest-developing area of evolutionary biology. Directed toward an undergraduate audience, the text emphasizes the interplay between theory and empirical tests of hypotheses, thus acquainting students with the process of science. It addresses major themes--including the history of evolution, evolutionary processes, adaptation, and evolution as an explanatory... View Details
Evolutions: Fifteen Myths That Explain Our World
by Oren Harman (Author)
A brilliant lyrical exploration of how modern science illuminates what it means to be human, from the award-winning author of The Price of Altruism
We no longer think, like the ancient Chinese did, that the world was hatched from an egg, or, like the Maori, that it came from the tearing-apart of a love embrace. The Greeks told of a tempestuous Hera and a cunning Zeus, but we now use genes and natural selection to explain fear and desire, and physics to demystify the workings of the universe.
Science is an astounding achievement, but are we really any wiser... View Details
Evolution: The Human Story
by DK (Author)
How did we develop from simple animals inhabiting small pockets of forest in Africa to the dominant species on Earth? Traveling back almost eight million years to our earliest primate relatives, Evolution: The Human Story charts the development of our species from tree-dwelling primates to modern humans.
Investigating each of our ancestors in detail and in context, from the anatomy of their bones to the environment they lived in, Evolution: The Human Story profiles every human relative and ancestor discovered to date, and illustrates them in lifelike form.
Amazingly... View Details
Evolution: How We and All Living Things Came to Be
by Daniel Loxton (Author), Daniel Loxton (Illustrator)
Evolution is the process that created the terrible teeth of Tyrannosaurus rex and the complex human brain, clever enough to understand the workings of nature. Young readers will learn how a British naturalist named Charles Darwin studied nature and developed his now-famous concepts of natural selection and survival of the fittest. And how modern-day science has added to our understanding of the theory of evolution.
Can something as complex and wondrous as the natural world be explained by a simple theory? The answer is yes, and now Evolution explains how in a way that makes it easy... View Details
Evolution: Still a Theory in Crisis
by Michael Denton (Author)
More than thirty years after his landmark book Evolution: A Theory in Crisis (1985), biologist Michael Denton revisits his earlier thesis about the inability of Darwinian evolution to explain the history of life. He argues that there remains “an irresistible consilience of evidence for rejecting Darwinian cumulative selection as the major driving force of evolution.” From the origin of life to the origin of human language, the great divisions in the natural order are still as profound as ever, and they are still unsupported by the series of adaptive transitional forms predicted by... View Details
Evolution (Second Edition)
by Carl T. Bergstrom (Author), Lee Alan Dugatkin (Author)
Get your students thinking critically about evolution.Evolution presents foundational concepts through a contemporary framework of population genetics and phylogenetics that is enriched by current research and stunning art. In every chapter, new critical thinking questions and expanded end-of-chapter problems emphasizing data interpretation reinforce the Second Edition’s focus on helping students think like evolutionary biologists. View Details