Faculty Portrait

Contact Information

Name: Clayton J. Visger

Title: Associate Professor

Office Location: TSC 4013

Email: clayton.visger [at] csus.edu

Mailing Address: Sacramento State 6000 J Street Sacramento, CA 95819-6077

Office Hours: see biology department for updated OH

Courses That I Teach

Bio 1: Biodiversity, Evolution and Ecology

Bio 100: Introduction to Scientific Analysis

Bio 113: Evolution and Speciation in Flowering Plants

Bio 224: Genomics, Proteomics, and Bioinformatics

Research Projects/Interests

My research interests are in the evolutionary role of polyploidy, or whole-genome duplication, and how it functions as a speciation mechanism. I investigate the impact of polyploidy in flowering plants using genomic and bioinformatics methods, while drawing from the fields of physiology and ecology to place the findings into an evolutionary and ecological context.

Current funding:

2018 - present NSF IOS 1754072 Collaborative Research: RUI: Understanding the effects of ploidal level on responses to global change in plants

For more information please visit the Visger Lab research page.


  • Welch, C., Johnson, E., Tupikova, A., Anderson. J., Tinsley, B., Newman, J., Widman, E., Alfareh, A., Davis, A., Rodriguez, L., Visger, C.J., Miller-Schulze, J.P., Lee, W., & Mulligan, K. 2022. Bisphenol A affects neurodevelopmental gene expression, cognative function, and neuromuscular synaptic morphology in Drosophila melanogasterNeurotoxicology DOI: 10.1016/j.neuro.2022.01.006
  • Morris, A. B., Baskauf, C. J., Diggs, J. T., Egan, A. N., Lincicome, D., Mandel, J. R., & Visger, C. J. (2021). Conserving the Flora of Limestone Cedar Glade Communities of the Southeastern United States. In Reference Module in Earth Systems and Environmental Sciences. Elsevier.
  • Blais, S.J. (Mentor: C.J. Visger). 2020. Developing Clarkia rhomboidea as a natural cytogenetics model for allopolyploidy. McNair Scholars Journal
  • Visger, C.J., G.K-S. Wong, Y. Zhang, P.S. Soltis, and D.E. Soltis. 2019. Divergent gene expression levels between diploid and autotetraploid Tolmiea relative to the total transcriptome, the cell, and biomass. American Journal of Botany DOI:10.1002/ajb2.1239
  • Folk, R.A., C.J. Visger, P.S. Soltis, D.E. Soltis, and R.P. Guralnick. 2018. Geographic range dynamics drove ancient hybridization in a lineage of angiosperms. The American Naturalist DOI: 10.1086/698120
  • Visger, C.J., G.K-S. Wong, Y. Zhang, P.S. Soltis, and D.E. Soltis. 2017. Using synthetic spike-in RNAs to quantify expression level divergence following autopolyploidy. 2017. bioRxiv DOI: 10.1101/169367 *preprint of Visger et al. 2019
  • Soltis, D.E. and C.J. Visger. 2016. Polyploid speciation. Oxford bibliographies in evolutionary biology. Ed. Jonathan Losos. Oxford University Press. New York, New York, USA
  • Visger, C.J., C. Germain-Aubrey, M. Patel, P.S. Soltis, and D.E. Soltis. 2016. Niche divergence between diploid and autopolyploid Tolmiea. American Journal of Botany DOI:10.3732/ajb.1600130
  • Soltis, D.E., C.J. Visger, D.B. Marchant, and P.S. Soltis. 2016. Polyploidy: Pitfalls and paths to a paradigm. American Journal of Botany DOI:10.3732/ajb.1500501
  • Crowl, A., N.W. Miles, C.J. Visger, K. Hansen, T. Ayers, R. Haberle, and N. Cellinese. 2016. A global perspective on Campanulaceae: Biogeographic, genomics, and floral evolution. American Journal of Botany DOI:10.3732/ajb.1500450
  • Wolf, P.G., E.B. Sessa, D.B. Marchant, F-W. Li, C.J. Rothfels, E.M. Sigel, M.A. Gitzendanner, C.J. Visger, J.A. Banks, D.E. Soltis, P.S. Soltis, K.M. Pryer, and J.P. Der. 2015. An exploration into fern genome space. Genome Biology and Evolution DOI:10.1093/gbe/evv163
  • Wolf, P.G., C.A. Rowe, J.P. Der, M.P. Schilling, Visger, C.J., and J.A. Thomson. 2015. Origins of Pteridium on Galapagos and other archipelagos. AoB Plants DOI:10.1093/aobpla/plv118
  • Servick*, S, C.J. Visger*, M.A. Gitzendanner, P.S. Soltis, and D.E. Soltis. 2015.  Population genetic variation, geographic structure, and multiple origins of autopolyploidy in Galax urceolata (Diapensiaceae). American Journal of Botany  DOI:10.3732/ajb.1400554        *Authors contributed equally
  • Crowl, A., C.J. Visger, G. Mansion, R. Hand, H. Wu, G. Kamari, D. Phitos, and N. Cellinese. 2015.  Evolution and biogeography of the endemic Roucela complex (Campanulaceae: Campanula) in the eastern Mediterranean. Ecology and Evolution DOI:10.1002/ece3.1791
  • Mavrodiev, E.V, M. Chester, V.N. Suárez-Santiago, C.J. Visger, R. Rodriguez, A. Susanna, R.M. Baldini, P.S. Soltis, and D.E. Soltis. 2015. Multiple origins and chromosomal novelty in the allotetraploid Tragopogon castellanus (Asteraceae). The New Phytologist DOI: 10.1111/nph.13227.
  • Soltis, D.E., C.J. Visger, and P.S. Soltis. 2014. The polyploidy revolution then...and now: Stebbins revisited. American Journal of Botany DOI:10.3732/ajb.1400178       -Recommended by the Faculty of 1000
  • Soltis, P.S., X. Liu, D.B. Marchant, C.J. Visger, and D.E. Soltis. 2014. Polyploidy and novelty: Gottlieb’s legacy. Philosophical Transactions of the Royal Society B Biological Sciences DOI:10.1098/rstb.2013.0351