Research Interests
My research integrates the analysis of molecular sequence
variation with laboratory physiology and field ecology to address fundamental
questions about the origins and maintenance of microbial diversity in nature.
How do microorganisms adapt to novel environments? Does adaptation come with
evolutionary costs? Are changes in ecology always adaptive? How do
evolutionary processes, environmental variation and geography combine to produce
the patterns of genotypic and phenotypic diversity observed in microbial
populations? I focus on the evolution of environmental tolerance in
cyanobacteria, an ancient group of photosynthetic bacteria found in a wide range
of habitats. Current projects investigate: (1) the genetic basis of temperature
adaptation in a group of hot spring cyanobacteria (Synechococcus) living
at or near the thermal limit for photosynthetic life; (2) how microevolutionary
processes and demographic factors shape the distribution, nitrogen metabolism
and thermotolerance of the thermophilic cyanobacterium Mastigocladus at
different geographic scales; and (3) the molecular evolution of a novel
cyanobacterial light harvesting system based on chlorophyll d.
I currently have support
for a graduate student research assistant to investigate the thermal performance
of the Calvin cycle enzyme RuBisCO in ecologically differentiated
Synechococcus with molecular evolutionary, biochemical and physiological
approaches.