More isn’t always better when it comes to DNA
Great, wonderful, wacky things can come in small genomic packages.
Credit: Enrique Ibarra-Laclette and Claudia Anahí Pérez-Torres.
Light micrograph of the bladder of the carnivorous bladderwort plant, Utricularia gibba. A new study finds that this marvelous plant houses more genes than several well-known species, such as grape, coffee or papaya — despite having a much smaller genome.
Credit: Enrique Ibarra-Laclette, Claudia Anahí Pérez-Torres and Paulina Lozano-Sotomayor.
Scanning electron micrograph of the bladder of Utricularia gibba, the humped bladderwort plant (color added). The plant is a voracious carnivore, with its tiny, 1-millimeter-long bladders leveraging vacuum pressure to suck in tiny prey at great speed.
That’s one lesson to be learned from the carnivorous bladderwort, a plant whose tiny genome turns out to be a jewel box full of evolutionary treasures.
Called Utricularia gibba by scientists, the bladderwort is a marvel of nature. It lives in an aquatic environment. It has no recognizable roots. It boasts floating, thread-like branches, along with miniature traps that use vacuum pressure to capture prey.
A new study in the scientific journal Molecular Biology and Evolution breaks down the plant’s genetic makeup, and finds a fascinating story.
According to the research, the bladderwort houses more genes than several well-known plant species, such as grape, coffee or papaya — despite having a much smaller genome.
This incredibly compact architecture results from a history of “rampant” DNA deletion in which the plant added and then eliminated genetic material at a very fast pace, says University at Buffalo Professor of Biological Sciences Victor Albert, who led the study.
“The story is that we can see that throughout its history, the bladderwort has habitually gained and shed oodles of DNA,” he says.
“With a shrunken genome,” he adds, “we might expect to see what I would call a minimal DNA complement: a plant that has relatively few genes — only the ones needed to make a simple plant. But that’s not what we see.”
A unique and elaborate genetic architecture
In contrast to the minimalist plant theory, Albert and his colleagues found that U. gibba has more genes than some plants with larger genomes, including grape, as already noted, and Arabidopsis, a commonly studied flower.
A comparison with the grape genome shows U. gibba’s genetic opulence clearly: The bladderwort genome, holding roughly 80 million base pairs of DNA, is six times smaller than the grape’s. And yet, the bladderwort is the species that has more genes: some 28,500 of them, compared to about 26,300 for the grape.
U. gibba is particularly rich in genes that may facilitate carnivory — specifically, those that enable the plant to create enzymes similar to papain, which helps break down meat fibers. The bladderwort is also rich in genes linked to the biosynthesis of cell walls, an important task for aquatic species that must keep water at bay.
“When you have the kind of rampant DNA deletion that we see in the bladderwort, genes that are less important or redundant are easily lost,” Albert says. “The genes that remain — and their functions — are the ones that were able to withstand this deletion pressure, so the selective advantage of having these genes must be pretty high.
“Accordingly, we found a number of genetic enhancements, like the meat-dissolving enzymes, that make Utricularia distinct from other species.”
Much of the DNA the bladderwort deleted over time was noncoding “junk DNA” that contains no genes, Albert says.
High gene turnover
The study included partners from UB, the Universitat de Barcelona in Spain, the Laboratorio Nacional de Genómica para la Biodiversidad (LANGEBIO) in Mexico and the Instituto de Ecología in Mexico.
To determine how the bladderwort evolved its current genetic structure, the team compared the plant to four related species. What they uncovered was a pattern of rapid DNA alteration.
As Albert explains, “When you look at the bladderwort’s history, it’s shedding genes all the time, but it’s also gaining them at an appreciable enough rate, permitting it to stay alive and produce appropriate adaptations for its unique environmental niche.”
In the realm of DNA gain, the study found that U. gibba has undergone three duplication events in which its entire genome was replicated, giving it redundant copies of every gene.
This fast-paced gene gain was balanced out by swift deletion. Evidence for this phenomenon comes from the fact that the plant has a tiny genome despite its history of genetic duplication. In addition, the plant houses a high percentage of genes that don’t have close relatives within the genome, which suggests the plant quickly deleted redundant DNA acquired through duplication events.
The study was supported by the National Science Foundation. It builds on the work of Albert and other team members, who reported in the journal Nature in 2013 that the bladderwort’s genome was comprised almost entirely of useful, functional genes and their controlling elements, in contrast to species like humans, whose genomes are more than 90 percent “junk DNA.”
Contact: Charlotte Hsu, email@example.com
University at Buffalo
Charlotte Hsu | newswise
22.07.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau
Regulation of root growth from afar: How genes from leaf cells affect root growth
22.07.2019 | Max-Planck-Institut für Molekulare Pflanzenphysiologie
Adjusting the thermal conductivity of materials is one of the challenges nanoscience is currently facing. Together with colleagues from the Netherlands and Spain, researchers from the University of Basel have shown that the atomic vibrations that determine heat generation in nanowires can be controlled through the arrangement of atoms alone. The scientists will publish the results shortly in the journal Nano Letters.
In the electronics and computer industry, components are becoming ever smaller and more powerful. However, there are problems with the heat generation. It is...
Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.
Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...
Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.
Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...
For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.
Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...
An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".
The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
22.07.2019 | Physics and Astronomy
22.07.2019 | Life Sciences
22.07.2019 | Earth Sciences