George Somero Website: Somero Lab
Adaptations in proteins play critical roles in allowing organisms to colonize habitats with temperatures ranging from Antarctic cold to hot-spring 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 which 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 Centigrade 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, for instance, 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. On-going 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. The physiology of invasive species is a recent focus of the laboratory. Physiological differences between native and invasive congeners of marine mussels are being studied in an attempt to define what makes a species a good invader and what environmental conditions may set the limits of the invasive process. 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, University of California at Santa Barbara, University of California at Davis, Arizona State University, Purdue University, The University of Florida, the University of Colorado, the University of Miami, San Francisco State University, the University of San Diego, Louisiana State University, and Whitman College. Selected PublicationsPodrabsky, 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. J. Exp. Biol. 207: 2237-2254. 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. Biol. Bull. 208: 138-144. 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. Mar. Biol.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. J. Exp. Biol., 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) J. Exp. Biol. 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. J. Exp. Biol. 209: 2660-2677. Podrabsky, J.E., and G.N. Somero (2006). Inducible heat tolerance in Antarctic notothenioid fishes. Polar Biol. DOI 10.1007/s00300-006-0157-y. 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. Stokes, M.D. and G.N. Somero. 1999. An optical oxygen sensor and reaction vessel for high-pressure applications. Limnology and Oceanography. 44(1):189-195. 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. Somero, G.N. 1992. Adaptations to high hydrostatic pressure. Annual Review of Physiology. 54:557-577. Somero, G.N., C.B. Osmond, and L. Bolis (eds). 1992. Water and Life. Springer-Verlag, Heidelberg. |
George N. Somero received his Ph.D. from Stanford University. His group studies the effects of environmental factors—temperature, salinity, hydrostatic pressure, and oxygen availability—on marine animals. Their studies of molecular evolution focus on macromolecular adaptations, for instance, 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.