George Somero

George Somero
David & Lucile Packard Professor in Marine Sciences
Biochemical Adaptation and Evolution, Ecological Physiology

Associate Director of Hopkins Marine Station
(831) 655-6243

Website: Somero Lab

George SomeroGeorge N. Somero received his Ph.D. from Stanford University. His group studies the effects of environmental factors such as temperature, salinity, hydrostatic pressure and oxygen availability on marine animals. Their studies of molecular evolution focus on macromolecular adaptations such as changes in protein structure that underlie adaptive variation in functional properties and stability and "micromolecular" adaptations that provide the appropriate intracellular milieu for macromolecular function. Studies of short-term responses to environmental change use DNA microarray technology to follow shifts in gene expression in marine organisms.

Adaptations in proteins play critical roles in allowing organisms to colonize habitats with temperatures ranging from Antarctic cold to hotspring heat. Professor Somero's group has shown that adaptation in orthologous forms of enzymes involves amino acid substitutions that lie outside of the active site and that cause changes in conformational flexibility of the proteins. Adaptive variation may be achieved by only a single amino acid substitution in some cases. Temperature changes of only a few degrees Celsius are adequate to favor selection for adaptive change, a finding that is relevant to concerns about global climate change.

In the context of climate change, studies of the thermal tolerance limits of such physiological processes as protein synthesis, induction of the heat-shock response, heart function and nerve conduction are showing that certain marine species may currently live near the upper limits of their thermal tolerance ranges. Species living at high temperatures, such as animals from the upper intertidal zone, seem less able to adapt to warming than related species found in cooler habitats, such as the subtidal zone. Ongoing studies are being conducted to reveal further aspects of the effects of global warming on marine species in an attempt to allow predictions of how this warming may affect biogeographic patterning with latitude and along vertical gradients.

Species being studied include Antarctic notothenioid fishes, which die of heat death at a chilly 4ーC. Ongoing studies at the Antarctic base at McMurdo Sound are testing the hypothesis that, during their approximately 14 million years of evolution in a constant temperature "ice bath," these fishes have lost many of the gene regulatory capacities needed to adjust physiological systems to increases in temperature. Loss of this genetic information could greatly limit the abilities of these Antarctic species to withstand climate change.

Professor Somero received a Guggenheim Fellowship and is a member of the National Academy of Sciences and a fellow of the American Association for the Advancement of Science.

Members of Professor Somero's laboratory have joined faculties at the University of California at San Diego, Santa Barbara and Davis; California Polytechnic State University-San Luis Obispo, the University of Southern California, the College of William and Mary, Purdue University, the University of Ottawa, San Francisco State University, the University of San Diego, Santa Clara University, Louisiana State University, Portland State University, the University of Wisconsin and Whitman College.

Selected Publications

Somero, G.N. 2010. The physiology of climate change: how potentials for acclimatization and genetic adaptation will determine "winners" and "losers."  Journal of Expermental Biolology. 213: 912-920.

Gracey, A.Y., M. Chaney, J. Boomhower, W. Tyburczy, K. Connor and G.N. Somero. 2008. Rhythms of gene expression in a fluctuating intertidal environment. Current Biology. 18: 1501-1507.

Dong, Y. and G.N. Somero. 2008. Temperature adaptation of cytosolic malate dehydrogenases of limpets (genus Lottia): differences in stability and function due to minor changes in sequence correlate with biogeographic and vertical distributions. Journal of Experimental Biololgy. 212: 169-177.

Dong, Y., L.P. Miller, J. G. Sanders, and G.N. Somero. 2008. Heat-shock protein 70 (Hsp 70) expression in four limpets of the genus Lottia: Interspecific variation in constitutive and inducible synthesis correlates with in situ exposure to heat stress. Biological Bulletin. 215: 173-181.

Evans, T. and G.N. Somero. 2008. A microarray-based transcriptomic time-course of hyper- and hypoosmotic signaling events in the euryhaline fish Gillichthys mirabilis: osmosenors to effectors. Journal of Experimental Biology. 211: 3636-3649.

Somero, G.N. 2008. Clifford Ladd Prosser, A Biographical Memoir. National Academy of Sciences, Washington, D.C.

Pörtner, H.O., G.N. Somero, and L. Peck. 2007. Thermal limits and adaptation in marine Antarctic ectotherms: an integrative view. Proceedings of the Royal Society of London B - Biological Sciences. 362:2233-2258.

Podrabsky, J.E., and G.N. Somero. 2007. An inducible 70 kDa-class heat shock protein is constitutively expressed during early development and diapause in annual killifish, Austrofundulus limnaeus. Cell Stress & Chaperones, 12: 199-204.

Podrabsky, J.E., J.P. Lopez, T.W.M. Fan, R. Higashi, and G.N. Somero. 2007. Extreme anoxia tolerance in embryos of the annual killifish Austrofundulus limnaeus: Insights from a metabolomics analysis. Journal of Experimental Biology. 210: 2253-2266.

Somero, G.N. 2007. Heat stress. In: M.W. Denny and S. Gaines (eds.). Tidepool Encyclopedia, pp. 266-270. Los Angeles, University of California Press.

Braby, C.E., and G.N. Somero. 2006. Ecological gradients and relative abundance of native (Mytilus trossulus) and invasive (M. galloprovincialis) blue mussels in the California hybrid zone. Marine Biology.148: 1249-1262.

Fields, P.A., E. Rudomen and G.N. Somero. 2006. Temperature sensitivities of cytosolic malate dehydrogenases from native and invasive species of marine mussels (genus Mytilus): sequence-function linkages and correlations with biogeographic distribution. Journal of Experimental Biology. 209: 656-677.

Braby, C.E., and G.N. Somero. 2006. Following the heart: temperature and salinity effects on heart rate in native and invasive species of blue mussels (genus Mytilus). Journal of Experimental Biology. 209: 2554-2566.

Buckley, B.A., A.Y. Gracey, and G.N. Somero. 2006. The cellular response to heat stress in the goby Gillichthys mirabilis: a cDNA microarray and protein-level analysis. Journal of Experimental Biology. 209: 2660-2677.

Stenseng, E., C. Braby, and G.N. Somero. 2005. Evolutionary and acclimation-induced variation in the thermal limits of heart function in congeneric marine snails (genus Tegula): Implications for vertical zonation. Biological Bulletin. 208: 138-144.

Podrabsky, J., and G.N. Somero. 2004. Changes in gene expression associated with acclimation to constant temperatures and fluctuating daily temperatures in an annual killifish Austrofundulus limnaeus. Journal of Experimental Biology. 207: 2237-2254.

Hochachka, P.W. and G.N. Somero. 2002. Biochemical adaptation : mechanism and process in physiological evolution. Oxford ; New York : Oxford University Press.

Fields, P.A., et al. 2002. Temperature adaptation in Gillichthys (Teleost : Gobiidae) A(4)-lactate dehydrogenases: identical primary structures produce subtly different conformations. Journal of Experimental Biology. 205(9):1293-1303.

Tomanek, L. and G.N. Somero. 2002. Interspecific- and acclimation-induced variation in levels of heat-shock proteins 70 (hsp70) and 90 (hsp90) and heat-shock transcription factor-1 (HSF1) in congeneric marine snails (genus Tegula): Implications for regulation of hsp gene expression. Journal of Experimental Biology. 205(5):677-685.

Kawall, H.G., et al. 2002. Metabolic cold adaptation in Antarctic fishes: evidence from enzymatic activities of brain. Marine Biology. 140(2):279-286.

Lin, J.-J, et al. 2002. Phylogenetic relationships and biochemical properties of the duplicated cytosolic and mitochondrial isoforms of malate dehydrogenase from a teleost fish, Sphyraena idiastes. Journal of Molecular Evolution. 54(1):107-117.

Fields, P.A., B.D. Wahlstrand, and G.N. Somero. 2001. Intrinsic versus extrinsic stabilization of enzymes: The interaction of solutes and temperature on A4-lactate dehydrogenase orthologs from warm-adapted and cold-adapted marine fishes. European Journal of Biochemistry. 268(16):4497-4505.

Stillman, J.H. and G.N. Somero. 2001. A comparative analysis of the evolutionary patterning and mechanistic bases of lactate dehydrogenase thermal stability in porcelain crabs, genus Petrolisthes. Journal of Experimental Biology. 204(4):767-776.

Gracey, A.Y., J.V. Troll, and G.N. Somero. 2001. Hypoxia-induced gene expression profiling in the euryoxic fish Gillichthys mirabilis. Proceedings of the National Academy of Sciences USA. 98(4):1993-1998.

Hofmann, G.E., et al. 2000. Heat-shock protein expression is absent in the Antarctic fish Trematomus bernacchii (family Nototheniidae). Journal of Experimental Biology. 203(15):2331-2339.

Somero, G.N. 2000. Unity in diversity: A perspective on the methods, contributions, and future of comparative physiology. Annual Review of Physiology. 62:927-937.

Stillman, J. and G.N. Somero. 2000. A comparative analysis of the upper thermal tolerance limits of eastern Pacific porcelain crabs, genus Petrolisthes: Influences of latitude, vertical zonation, acclimation, and phylogeny. Physiological and Biochemical Zoology. 73(2):200-208.

Tomanek, L., and G.N. Somero. 2000. Time course and magnitude of synthesis of heat-shock proteins in congeneric marine snails (Genus Tegula) from different tidal heights. Physiological and Biochemical Zoology. 73:249-256.

Somero, G.N. 2000. Unity in diversity: A perspective on the methods, contributions, and future of comparative physiology. Annual Review of Physiology. 62:927-937.

Tomanek, L. and G.N. Somero. 1999. Evolutionary and acclimation-induced variation in the heat-shock responses of congeneric marine snails (genus Tegula) from different thermal habitats: Implications for limits of thermotolerance and biogeography. Journal of Experimental Biology. 202(21):2925-2936.

Fields, P.A. and G.N. Somero. 1998. Hot spots in cold adaptation: localized increases in conformational flexibility in lactate dehydrogenase A-4 orthologs of Antarctic notothenoid fishes. Proceedings of the National Academy of Sciences USA. 95:11476-11481.

Somero, G.N. 1995. Proteins and temperature. Annual Review of Physiology. 57:43-68.