George Somero's Profile
George Somero is part of Stanford Profiles, official site for faculty, postdocs, students and staff information (Expertise, Bio, Research, Publications, and more). The site facilitates research and collaboration in academic endeavors.
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Current Research and Scholarly Interests

RESEARCH INTERESTS: The unifying theme in our research is adaptation of organisms to the environment. We seek to determine how different environmental factors, notably temperature and the threat of desiccation, affect organisms, and how organisms respond adaptively to these perturbations. Proteins are a primary study system in most of our work. We are documenting how adaptive change in protein sequence (primary structure) achieves the conservation of critical functional and structural characteristics of enzymatic and structural proteins. These studies exploit homologous (orthologous) proteins from differently adapted species, frequently congeneric species adapted to only slightly different temperatures. We are using these comparative studies not only to examine adaptation to environment, but also to deduce basic structure-function relationships in proteins. For example, we are delineating the sites in the primary and higher orders of protein structure where adaptive change is permissible. Mapping of adaptively important changes in orthologs of closely related congeners supports the hypothesis that much of the protein molecule contributes to the energy changes that accompany catalysis.

Our studies of proteins are performed in solution conditions that mimic the intracellular conditions encountered by the proteins. The use of in vitro media that simulate in vivo conditions has enabled us to demonstrate that the “micromolecules” of the cell, that is, the small solutes that bathe macromolecules, contribute importantly to the establishment of the functional and structural properties of proteins. Macromolecular and micromolecular evolution play complementary roles in adaptation to environment.

Our field studies focus on “real world” effects of temperature on protein systems. A primary focus of these studies is to determine how changes in environmental temperature affect the latitudinal and depth distribution patterns of marine organisms. These studies demonstrate that many organisms live close to the upper thermal limits of protein structure and function, and suggest that global warming may have pronounced effects on ectothermic (“cold-blooded”) animals.

Studies of thermal effects at the molecular level are complemented by physiological investigations, for example, of heart function. The results of the physiological studies also indicate that only slight increases in maximal habitat temperature are likely to have profound negative effects on many marine animals. Paradoxically, the most warm-adapted species appear in many cases to be the most threatened by further increases in temperature, such as those that may result from continued global climate change. Our physiological studies also focus on an invasive species of mussel which has replaced a native mussel along much of the California coast. We have identified differences in cardiac function and enzymatic activity that may account for the competitive advantage of the invader and allow predictions to be made of how effectively it will colonize habitats to the north of its present distribution range.

We are using DNA microarray (“gene chip”) technology to monitor shifts in gene expression in response to environmental change (alterations in oxygen availability, salinity, and temperature). Among our goals in using these new approaches is the elucidation of the molecular bases of the different capacities of species to respond adaptively to environmental changes.