Normark speaks on Studies of Evolution of Unusual Genetic Systems


When it comes to sex, the roundworm Diploscapter pachys is a loner. Abstinence may have found its most impressive poster child yet: Diploscapter pachys. The tiny worm is transparent, smaller than a poppy seed and hasn't had sex in 18 million years.
It has basically just been cloning itself this whole time. Usually, that is a solid strategy for going extinct, fast. What is its secret?
"Scientists have been trying to understand how some animals can survive for millions of years without sex, because such strict, long-term abstinence is very rare in the animal world," says David Fitch, a biologist at New York University. Most plants and animals use sex to reproduce.
Photo courtesy of Karin Kiontke and David Fitch/NYU

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Baskin Receives DOE Grant to Study Plant Growth

Tobias Baskin, biology, recently received a $238,000 grant from the Department of Energy to study cellulose and plant control of anisotropic growth, that is, growth rates that are not equal in all directions.

As he explains, “Anisotropy is a hallmark of plant growth. Almost without exception, cells grow faster in one direction than in another.” He will study such questions as how a plant makes organs with specific and heritable shapes, for example, how it builds flat leaves appropriate for catching the sun’s rays and cylindrical roots for foraging soil nutrients.

“In plants, the shapes of organs are controlled by growth. When growth is the same in all directions, it is isotropic, and this kind of growth gives rise to spherical structures, such as a blueberry,” he points out. However, “most plant organs are far from spherical and require growth to differ in different directions, that is to be anisotropic. Growth in plant cells is powered by hydrostatic pressure, which in typical plant cells exceeds that of the typical automobile tire, and is controlled by the mechanical anisotropy of the cell wall.”

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Alexander Gerson Studies Native Songbirds at Risk in a Warming Climate

When it’s 120 degrees in Phoenix, it’s not only planes that aren’t flying. Desert birds are also grounded—hunkered down in the shade until it cools off—but if they stay too long, they can weaken from dehydration and be unable to replenish their water. It’s a vicious cycle, one that UMass Amherst is collaborating with other universities to understand.

“The uniqueness of this collaboration arises from the way it combines climate mapping and geographic information with physiological data,” says Alexander Gerson, Assistant
Professor of Biology, who contributed his expertise in how birds handle thermal stress to the study.

Using land-surface modeling and hourly temperature maps, the team projected the potential effects of current and future heat waves on lethal dehydration in birds and how rapidly this can occur in species native to the Sonoran Desert. Their models revealed that increasing air temperatures and heat wave occurrences will potentially affect the water balance, daily activity patterns, and geographic distribution of arid-zone birds. Some regions of the desert could become uninhabitable for many species, and future high-temperature events could depopulate whole regions—as they have with mass avian die-offs occurring in Australia and South Africa.

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Peg Riley Joins Board of Alliance for the Prudent Use of Antibiotics

Biology professor Margaret Riley, an expert in the evolution of microbial resistance, is one of five new members of the board of directors of the Boston-based Alliance for the Prudent Use of Antibiotics (APUA). The appointments were announced in June.

Stuart B. Levy, APUA’s CEO, said, “Our new board members occupy the highest levels of academic research, medicine, biopharmaceuticals and veterinary science. Their areas of expertise harmonize to address the complexity of antimicrobial resistance. We welcome them.”

Riley says, “I am honored to be invited to serve on the board of directors for APUA, which was one of the very first organizations devoted to informing the public of the dangers of antibiotic overuse and abuse and has been a key player in efforts to extend the lifespan of these life-saving drugs.”

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Evolutionary Biologist Craig Albertson Identifies Non-genetic Source of Species Variability

An unspoken frustration for evolutionary biologists over the past 100 years, says Craig Albertson at the University of Massachusetts Amherst, is that genetics can only account for a small percentage of variation in the physical traits of organisms. Now he reports experimental results on how another factor, a “bizarre behavior” that is part of early cichlid fish larvae’s developmental environment, influences later variation in their craniofacial bones.

Albertson has studied African cichlid fish for 20 years as a model system for exploring how biodiversity originates and is maintained, with a focus on genetic contributions to species differences. In a new series of experiments with former Ph.D. student Yinan Hu, now a postdoctoral fellow at Boston College, they examined a “vigorous gaping” behavior in larval fish that starts immediately after the cartilaginous lower jaw forms and before bone deposition begins. Results appear in the current early online issue of Proceedings of the Royal Society B.

As Albertson explains, “We predicted that the baby fish are exercising their jaw muscles, which should impose forces on the bones they attach to, forces that might stimulate bone formation.” Albertson and Hu observed that gaping frequency, which could reach as high as 200 per minute, varied by species “in a way that foreshadows differences in bone deposition around processes critical for the action of jaw opening.”

Read more in the Royal Society Publishing article