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, firstname.lastname@example.org
University at Buffalo
Charlotte Hsu | newswise
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