Representation of a DNA transposon jumping into a gene to make a new intron. Courtesy of Jason Huff.
In the genomes of complex organisms, including humans, gene regions are often interrupted by segments—called introns—that must be removed for proteins to be correctly produced. Biologists were surprised to find these interrupting segments four decades ago. Since then, the origins of introns have become ever more mysterious, as evidence accumulated for an irregular history, with relatively few points in evolution during which a lot of new introns were made. This appears at odds with introns being so ubiquitous in modern genomes.
How are so many introns made? And why did introns accumulate so unevenly? A study published in Nature last week by CNR researchers Jason Huff and Daniel Zilberman, in collaboration with Scott Roy of San Francisco State University, begins to answer these questions.
Huff, a former postdoctoral researcher in the Department of Plant and Microbial Biology (PMB), is director of the QB3 Computational Genomics Resource Laboratory. Zilberman is an associate professor in PMB.
To identify a mechanism to make introns, the authors studied two very distantly related and poorly understood algae that have a lot of fairly new introns. They found that the new introns come from genetic elements, known as DNA transposons, that jump around genomes and can land in genes in such a way that they are removed correctly on the way to protein production. DNA transposons can proliferate rapidly in genomes for a while and then stop, explaining why introns are generated in dramatic episodes. The evolutionary distances between the two organisms and their transposons reveal that the two cases arose independently, suggesting that the mechanism the authors describe could be a general explanation for how introns are made.Read More Friday, October 28, 2016 - 15:15Legacy: section header item: Date: Friday, October 28, 2016 - 15:15headline_position: Top Leftheadline_color_style: Normalheadline_width: Longcaption_color_style: Normalcaption_position: Bottom Left
MCB Assistant Adjunct Professor Jacob Corn was one of the lead authors on a recent study revealing significant progress in the fight against sickle cell disease.
According to the report, “The field of environment and ecology includes subjects such as environmental health, environmental monitoring and management, and climate change” as well as the relationships between living things and the physical world. The report states that topics in the plant and animal science category include plant research, plant pathology, plant nutrition, veterinary medicine, marine and freshwater biology, and zoology.
CNR is honored to be a part of the campus community conducting groundbreaking research, teaching, and outreach in these subject areas.
UC Berkeley placed fourth in the overall global university ranking. Other highly ranked subject areas at Berkeley include Chemistry, Mathematics, Physics, Biology and Biochemistry, Microbiology, Engineering, and Space Science.Image: Date: Thursday, October 27, 2016 - 16:15Legacy: section header item: Date: Thursday, October 27, 2016 - 16:15headline_position: Top Leftheadline_color_style: Normalheadline_width: Longcaption_color_style: Normalcaption_position: Bottom Left
Each year, the MCB Department chooses five outstanding postdoctoral fellows for their excellence in research, contributions to their division, the department, and for their mentoring and outreach efforts.
An unprecedented 40-year experiment in a 40,000-acre valley of Yosemite National Park strongly supports the idea that managing fire, rather than suppressing it, makes wilderness areas more resilient to fire, with the added benefit of increased water availability and resistance to drought.After a three-year, on-the-ground assessment of the park’s Illilouette Creek basin, UC Berkeley researchers concluded that a strategy dating to 1973 of managing wildfires with minimal suppression and almost no preemptive, so-called prescribed burns has created a landscape more resistant to catastrophic fire, with more diverse vegetation and forest structure and increased water storage, mostly in the form of meadows in areas cleared by fires.
Graduate student Kate Wilkin gathering data in the field in the Illilouette Creek Basin, which bears the scars of many natural fires. Photo by Gabrielle Boisramé.
“When fire is not suppressed, you get all these benefits: increased stream flow, increased downstream water availability, increased soil moisture, which improves habitat for the plants within the watershed. And it increases the drought resistance of the remaining trees and also increases the fire resilience because you have created these natural firebreaks,” said Gabrielle Boisramé, a graduate student in UC Berkeley’s Department of Civil and Environmental Engineering and first author of the study.
Boisramé and co-author Sally Thompson, a UC Berkeley ecohydrologist and assistant professor of civil and environmental engineering, found that even in the drought years covered by the study, the basin retained more water than similar areas outside the park. That translated into more runoff into the Upper Merced River, which flows through Yosemite Valley, at a time when other rivers in the surrounding areas without a restored fire regime showed the same or decreased flow.
“We know that forests are deep-rooted and that they have a large leaf area, which means they are both thirsty and able to get to water resources,” Thompson said. “So if fire removes 20 percent of that demand from the landscape, that frees up some of the water to do different things, from recharging groundwater resources to supporting different kinds of vegetation, and it could start to move into the surface water supplies as stream flow.”
The study is published in the current issue of the journal Ecosystems.
If the results are confirmed from other studies, including the UC Berkeley team’s new project analyzing the Sugarloaf Creek Basin in Sequoia and Kings Canyon national parks, they could alter the way the federal government as well as water districts deal with fire, benefiting not only the forest environment but potentially also agriculture and cities because of more runoff into streams and reservoirs.
“I think it has the potential to change the conversation about wildfire management,” said co-author Scott Stephens, a fire expert and UC Berkeley professor of environmental science, policy and management who has studied the Illilouette basin since 2002.Monday, October 24, 2016 - 11:00byline: By Robert Sanders, UC Berkeley Media relations Legacy: section header item: Date: Monday, October 24, 2016 - 11:00headline_position: Top Leftheadline_color_style: Normalheadline_width: Longcaption_color_style: Normalcaption_position: Bottom Left
The Department of Molecular and Cell Biology (MCB) is soliciting applications for a new faculty member studying the biology of cancer; this position is open at any level (tenure-track or tenured). Rank will be determined by qualifications and experience. Potential start date is July 1, 2017.
Please note that the deadline for this search has been extended to October 31, 2016. If you have already submitted an application you do not need to reapply.
An international research consortium led by MCB scientists in the Harland and Rokhsar Labs, along with researchers at the University of Tokyo, "reports a striking pattern of genome duplication in the African clawed frog Xenopus laevis. The team showed that the frog’s genome arose through interspecific hybridizations of two now-extinct species between 15 and 20 million years ago."