Craig Everroad
rcraig@uoregon.edu
University of Oregon
Center for Ecology & Evolutionary Biology
5289 University of Oregon
Eugene, OR 97403-5289 USA
(541) 346-0454
Advisors:
Michelle Wood
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Phenotypic evolution and adaptation in picocyanobacteria
Research Interests:
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Marine picocyanobacteria are numerically some of the most abundant organisms on Earth and are major primary producers in the world's oceans. A given picocyanobacterium synthesizes a specific pigment compliment that determines its “spectral phenotype”, or in vivo fluorescence excitation and absorption spectra. These phenotypes dictate what wavelengths of light are biologically available for photosynthesis. Earlier data indicate that spectral phenotype is subject to natural selection; for bulk water distinct spectral phenotypes can be predictably correlated with the optical properties of the water they are found in, and the photosynthetic performance of strains with different spectral phenotypes are highest in the light fields to which they appear to be adapted. Despite the linkage between environment and phenotype, there is little congruence between distinct spectral phenotypes and the evolutionary history of marine picocyanobacterial lineages, and little is known about the mechanisms that allow picocyanobacterial communities to track changing optical conditions.
Any given spectral phenotype involves several biosynthetic pathways and dozens of genes. One aspect of the evolution of these phenotypes has been a stepwise increase in complexity (both at the genetic and macromolecular level) with each successive step facilitating expansion into a novel niche. It is known that gene duplication is important in the evolution of several of these pigment types, although other mechanisms (e.g. lateral gene transfer) are likely also important contributors. I am interested in understanding the evolutionary processes that account for the diversity of pigment types found in marine picocyanobacteria. I am trying to elucidate the molecular mechanisms that underlie the evolution of these complex traits by utilizing a multi-locus approach to examine the relationship between community level processes, specific pigment types, their underlying genotypes, and their evolutionary history.________________________
Publications
Wood, A.M, Everroad, R.C. and Wingard, L.M. 2005. Measuring Growth Rates in Microalgal Cultures. In Anderson, R. [Ed.] Algal Culturing Techniques. Phycological Society of America.
Everroad, C., Six, C., Partensky, F., Holztendorff, J., Thomas, J-C., and Wood, M. 2006. Biochemical Bases of Type IV Chromatic Adaptation in Marine Synechococcus spp. J. Bacteriology. 188:3345-3356 .
Everroad, R.C. and Wood, A.M. Comparative Molecular Evolution of Newly Discovered Picocyanobacterial Strains Reveals a Phylogeneticaly Informative Variable Region of b-Phycoerythrin. In Revision.