No evidence of genetic trade-offs in host plant use

Our paper examining constraints on the evolution of host use in the Melissa blue butterfly (Lycaeides melissa) was published in today’s issue of Molecular Ecology. We were interested in the potential for limited genetic variation or genetic trade-offs in performance on different host plants to slow or prevent adaptation to a novel host, in this case alfalfa. To address this question we conducted a massive larval rearing experiment (see the image below) and generated and analyzed partial genome sequences (GBS data) from the larvae (we also sequenced and assembled a draft whole genome for L. melissa to provide genomic context for our results). We found that L. melissa harbor genetic variation for performance on alfalfa and that genetic variants that affect performance on alfalfa do not affect performance on a native host plant. In other words, we found no evidence that genetic trade-offs limit diet breadth (cause host plant specialization) in these butterflies. I think this study shows how genomic data can be used to better test a classic hypothesis in evolutionary genetics.

Petri dishes with butterfly larvae.

Petri dishes with butterfly larvae.

New PhD students in the lab

Alberto de Rosa and Samridhi Chaturvedi joined the lab this fall. They are both PhD students. We are very excited to have them here.

Samridhi earned her B.Sc in Chemistry, Botany,  and Zoology from Christ College, Bangalore, India, and then earned her Masters in Applied Microbiology from the Vellore Institute of Technology, India. Her project focused on the genomic basis of Asthma. She then worked at the Indian Institute of Science on molecular phylogenetics of bufonid toads before joining the lab here.

Alberto de Rosa completed his M.Sc in Biodiversity and Evolution from the Università di Bologna in Italy. His thesis was on inter-specific pecking order of mixed groups of birds in semi-natural areas. He has since established an international network of collaborators to investigate the determinants of diversification in island Barn Owls in the Caribbean, with a focus on conservation applications of his research.

 

Paper on the genomic basis of parallel evolution published in Science

Check out our paper analyzing the genomic basis of parallel speciation in stick insects (Timema cristinae) that was just published in Science. We even made the cover! Science also published a related news piece discussing how our study sheds new light on the predictability of evolution. In this study we show that the repeated evolution of reproductive isolation between stick insects on different host plants involved parallel genetic differentiation at only a modest proportion of the genome, and thus genome divergence was mostly idiosyncratic. But, genetic regions that exhibit parallel divergence contain an excess of genes with specific functions, and are likely of central importance for speciation.

timemaSciCover

Summer fellowships and grants for Gompert Lab undergrads

Peter Nelson, Robert Olson, and Zach Valois were awarded summer research fellowships (SURCO’s) to work in the lab. This will provide a great opportunity for them to gain lab and field experience. Zach Valois was also awarded research grants from USU (URCO) and from the American Museum of Natural History (Theodore Roosevelt Memorial Fund). Zach presented preliminary findings form his funded project investigating parallel evolution in the Northern Scorpion at the USU Department of Biology Spring 2014 Undergraduate Research Symposium (pictured below).

zach_poster

USU Science Unwrapped

We were invited to participate in Utah State University’s Science Unwrapped series this April. After listening to a presentation from Paleontologist Mary Schweitzer, kids of all ages visited our booth to view an assortment of arachnids (provided by Zach Valois) and extract DNA from their cheek cells. They created necklaces from their DNA, which they took home with them. We all had a great time.

sciunwrapped

“Experimental evidence for ecological selection on genome variation in the wild” published in Ecology Letters

Our open access paper describing the genomic consequences of natural selection in experimental stick insect (Timema cristinae) populations was published in the March issue of Ecology Letters, and Aaron Comeault’s photo of the focal organism made the cover. I think this paper nicely demonstrates that genetic drift and selection can affect genome variation on ecological time scales, and also highlights the need to consider direct and indirect (linked or correlated) selection as determinants of allele frequency change at individual loci. You can read more about this study on Andrew Hendry’s Evo-Eco blog. cover

Graduate student positions for fall 2014 in evolutionary genetics and genomics

The Gompert lab at Utah State University (Department of Biology) is recruiting PhD students for Fall 2014. In our research we seek to better understand adaptation, speciation, and the determinants of genetic and phenotypic variation in nature. We work with a variety of organisms and use diverse approaches to investigate these topics. Most projects in the lab involve generating large, genome-scale DNA sequence data and applying existing or new statistical analyses to these data to test alternative hypotheses. You can read more about research in the Gompert lab here, https://gompertlab.wordpress.com/research/.

We are looking for students broadly interested in evolutionary genetics, genomics, or computational biology, and students with academic training in biology, statistics, or computer science are encouraged to apply. Potential research topics for these PhD students include (i) fluctuating selection and the maintenance of genetic variation in the wild, (ii) adaptation from standing variation in phytophagous insects, (iii) polygenic adaptation, (iv) hybridization and speciation, (v) the repeatability and predictability of evolution, and (vi) computational analyses of genome sequence variation. This is not an exhaustive list and students interested in alternative, but related research topics are also encouraged to apply. You can learn more about my expectations for graduate students and my mentoring approach here, https://gompertlab.wordpress.com/join-us/.

Graduate students accepted into the lab are provided financial support through Teaching Assistantships (TAs) or Research Assistantships (RAs). Interested students are also strongly encouraged to apply for graduate research fellowships, such as the National Science Foundation Graduate Research Fellowship. Importantly, students are eligible to apply for this and other fellowships in their final year as undergraduates. Additional funding exists for graduate student research and travel to scientific meetings.

Utah State University (USU) is a first-class research university located in the US Rocky Mountains. The faculty and graduate students at USU are highly interactive and include a great and diverse group of evolutionary biologists. The Gompert lab has ample computational and molecular resources for modern genome sequence analysis. We are also well-equipped for field work and lab or field experiments. Logan is a small town in northern Utah with a strong sense of community. The town is just minutes from great opportunities for outdoor recreation including mountain biking, rock climbing, cross-country and downhill skiing, and back-packing. Logan is also within a few hours of several national parks, major ski resorts, and world famous slickrock mountain biking.

Interested students are encouraged to e-mail me (zach.gompert@usu.edu). Please include a short description of your academic background and research interests and a CV. Prospective students need to submit a pre-application to the Biology Department (https://www.biology.usu.edu/htm/graduate-info/application-info/preapplication/), followed by a full application to the University. The full application is due on or before January 15th, 2014. Additional information about applying to the USU graduate program can be found here (http://www.biology.usu.edu/htm/graduate-info/application-info). USU and the Gompert lab are committed to providing equal educational and employment opportunities regardless of race, color, religion, sex, sexual orientation, national origin, socio-economic background, age, disability, or veteran status.

Zach Gompert
Assistant Professor

Department of Biology
Utah State University
Phone: 435 797-9463
e-mail: zach.gompert@usu.edu
Website: https://gompertlab.wordpress.com/