Insights into origin and evolution of strange virus-like elements

Some microorganisms produce nanostructures that morphologically and genetically resemble viruses, but don’t behave like typical viruses. Oddly, these structures package random pieces of DNA of their microbial host and, as a result, do not appear to propagate by infecting microbes and making more copies of themselves. Since these elements can deliver the packaged DNA to other cells, they were dubbed gene transfer agents (GTAs). It is not clear whether GTAs represent atypical viruses, defective viruses, or viruses co-opted by the microorganisms for some function. In a new study, Prof. Zhaxybayeva’s group used evolutionary analyses of GTA-like genes to show that a GTA in alpha-proteobacteria likely co-evolved with its bacterial host for at least 700 million years, suggesting that this GTA is unlikely to be a defective virus. The function of this GTA remains to be elucidated in the future work.

Bats and Bugs Do Battle in the Tropics

Professor Hannah ter Hofstede, Neukom Fellow Dr. Laurel Symes and biologist Dr. Sharon Martinson are interested in understanding the stratagies and trade-offs employed by insects that allow them to attract mates while trying to avoid notice by bat predators.  To learn more about their work, please see Joe Blumberg's article in Dartmouth News at this link:

Temperature fluctuations? What is on and what is off.

Every organism prefers a certain ambient temperature, but what happens when it experiences a change in temperature? Prof. Olga Zhaxybayeva and her colleagues at the University of Alberta have examined how an oil-dwelling bacterium Kosmotoga olearia, the current "record holder" of the growth temperature range, responds to temperature fluctuations.  In their paper in the Extremophiles journal, the researchers report that change in temperature affects about a quarter of this bacterium's genes and that gene duplication and horizontal gene transfer played an important role in this bacterium's ability to grow between 20 and 79 degrees Celsius.

Link to the paper:


Prof. Richard Holmes wins the New England Society Book Award

Prof. Richard Holmes has been awarded the New England Society Book Award for his book Hubbard Brook: The Story of a Forest Ecosystem (Yale University Press, 2016). Prof. Holmes and Dr. Gene E Likens co-authored this book, which highlights the remarkable and impactful long-term ecological research conducted at the Hubbard Brook Experimental Forest in New Hampshire’s White Mountains over the last 50 years.”  For more information about the award, please click here.

We welcome you to visit a display about Hubbard Brook on the second floor of the Class of 1978 Life Sciences Center.

Oxidative Damage Leads to Errors in Meiotic Chromosome Segregation

Research done in Prof. Sharon Bickel's lab has demonstrated that oxidative damage causes a premature loss of sister chromatid cohesion and an increase in chromosome segregation errors in Drosophila oocytes during meiosis. 

In women, the probability of miscarriage or Down Syndrome increases dramatically with age.  Studies of maternal age effect indicate that errors in female meiosis contribute significantly to this age-related effect.  The research done by the Bickel lab demonstrates that if oxidative damage contributes to maternal age effect then reducing oxidative damage could be a strategy for reducing chromosome segregation errors during meiosis.

Professor Sharon Bickel, MCB graduate student Adrienne Perkins, Class of 2013 undergraduate researcher Thomas Das and second year MCB graduate student Lauren Panzera contributed to this work.  These findings were published in the Proceeding of the National Academy of Sciences:

Youjun Wu named Copenhaver Fellow

Molecular and Cellular Biology Graduate Program Ph.D candidate, Youjun Wu, has been selected to be a John H. Copenhaver, Jr. and William H. Thomas, MD 1952 Fellow for her outstanding scholarship.  Youjun is a student in Prof. Erik Griffin's laboratory.  The laboratory studies cytoplasmic protein gradients that are involved in the patterning of early C. elegans embryos.

Youjun is first author on the Molecular Biology of the Cell research paper,  Coupling between cytoplasmic concentration gradients through local control of protein mobility in the Caenorhabditis elegans zygote.



Kudos to Biology Major Phi Beta Inductees and Sophmore Prize Winner!

Congratulations to Biology majors Dylan Cahil '18, Kennedy Jensen '18 and Nicholas Norwitz '18 on their induction into Dartmouth's Alpha Chapter of Phi Beta Kappa!  Dartmouth Phi Beta Kappa inductees must have one of the top twenty cummulative grade point averages after completing eight terms of study at Dartmouth.

Biology major, Anant Mishra '19 received the Phi Beta Kappa Sophmore Prize for holding one of the highest grade point averages in his class.  Congratulations Anant!

To read the article about the recipients in Dartmouth News, please visit this link:

Photo by Kate Soule.

"Beetle Mania" - Dartmouth Alumni Magazine features Prof. Matt Ayres

Prof. Matt Ayres is an internationally recognized expert on the effects of climate change on the impact and distribution insects.  In the Dartmouth Alumni Magazine article, "Beetle Mania" he talks about his work on the southern pine beetle, the impact of invasive, non-native insects and being summoned to the World Bank to discuss climate change and invasive insect species.

To read the full article, please click here.

Illustration by Gaby D’Alessandro

Bacterial Classification May be More Elusive than Previously Thought

Prof. Olga Zhaxybayeva's work on the classification of microorganisms has revealed that classifying microorganisms is more complicated than previously thought.  Her paper, A null model For mcrobial diversification published in Proceedings of the National Academy of Sciences of the United States of America, shows that a simple birth-death cycle of cells may explain grouping patterns.

To read the Dartmouth press release for this paper, please click here.

Sound Matters: Sex And Death In The Rain Forest

National Public Radio interviewed Dr. Laurel Symes, Dr. Sharon Martinson and Prof. Hannah ter Hofstede about their research on the sounds of the rain forest.  The group is studing the complex ultrasonic communications of bats and their insect prey.  The read or hear the full interview please visit the NPR website at the following link: