Janna Fierst

Janna  Fierst

Associate Professor


  • Ph.D., Biological Science, Florida State University, 2010
  • M.S., Biology, California State University Northridge, 2005
  • Postdoctoral research: Institute of Ecology and Evolution, University of Oregon

Research Interests

Research in my lab focuses around using theoretical, computational, and bioinformatic approaches to study fundamental questions in evolutionary genetics. There are two main themes in my research: 1) the influence of sex on genetic and genomic evolution; and 2) genetic networks in evolution. Below, I list some of the specific projects we are currently pursuing.

Sex in evolution

Sexual reproduction increases genetic variation through recombination, and that single difference results in a broad array of consequences at genetic and phenotypic levels. The division into two separate sexes results in different reproductive modes, mating systems, patterns of sexual dimorphism and sexual selection. Evolutionary theory predicts that populations and genomes should evolve differently depending on reproductive strategy, but until recently we could not generate the data necessary to test these fundamental theoretical predictions. Advances in sequencing technology and computing power mean that it is now possible to answer these questions. We currently focus on the consequences that sex has for genetic and genomic evolution.

Reproductive mode and genomic evolution in Caenorhabditis
Nematode worms in the genus Caenorhabditis descended from an outcrossing ancestor (with separate males and females). Three species independently evolved self-fertile hermaphroditism and these species also have the smallest genomes. We are investigating the differences in genome size and structure, and addressing the genetic and genomic differences caused by self-fertility. As part of this work, we are assembling genome sequences for outcrossing Caenorhabditis and developing machine learning methods to robustly identify contamination in de novo assemblies.

Network evolution

One of the central goals of biology is to understand how changes at a genetic level translate into phenotypic differences. Regulatory interactions, molecular networks, and system dynamics determine this relationship and understanding gene networks is a major focus of our research. ​We are interested in both how evolution shapes the structure and function of genetic networks, and how networks determine evolutionary outcomes. At an empirical level we are collaborating with the Phillips lab at the University of Oregon to map and manipulate the molecular networks underlying stress response pathways in nematode worms. At a theoretical level we use a combination of empirical data, computational and mathematical modeling to study the design principles that underlay the structure and function of genetic networks.

Selected Publications

Fierst, J.L., J.H. Willis, C.G. Thomas, W. Wang, R.M. Reynolds, T.E. Ahearne, A.D. Cutter, and P.C. Phillips. Reproductive mode and the evolution of genome size and structure in Caenorhabditis nematodes. PLoS Genetics 11(6): e1005323.

Fierst, J.L. 2015. Using linkage maps to correct and scaffold de novo genome assemblies: methods, challenges and computational tools. Frontiers in Genetics 6: 220.

Fierst, J.L. and P.C. Phillips. 2015. Modeling the evolution of complex of complex genetic systems: The gene network family tree. Journal of Experimental Zoology Series B 324:1-12.

Fierst, J.L. 2013. Female mating preferences determine system-level evolution in a gene network model. Genetica 141:157-170.

Fierst, J.L. and P.C. Phillips. 2012. Variance in epistasis links gene regulation and evolutionary rate in the yeast genetic interaction network. Genome Biology and Evolution 4: 1080-1087.

Fierst, J.L. 2011. A history of phenotypic plasticity accelerates evolution to a new environment. Journal of Evolutionary Biology 24:1992-2001.