Paper Reviewed
Narum, S.R. and Campbell, N.R. 2015. Transcriptomic response to heat stress among ecologically divergent populations of redband trout. BMC Genomics 16: 10.1186/s12864-015-1246-5.

In setting the stage for their contribution to the scientific literature, Narum and Campbell (2015) write that "thermal adaptation is a widespread phenomenon in organisms that are exposed to variable and extreme environments," while noting that whereas "some organisms may alter their distribution or behavior to avoid stressors and others may acclimate through physiological plasticity, many species evolve adaptive responses to local conditions over generations through natural selection," citing Dahloff and Rank (2000), Hoffman et al. (2003) and Kavanagh et al. (2010). In point of fact, they indicate that "evolutionary adaptation to local environments has been demonstrated across a wide variety of taxa" -- citing Keller and Seehausen (2012) -- "and is expected to play a critical role for species with limited dispersal capabilities."

In their investigation of one such case, the two researchers "tested for differential transcriptional response of ecologically divergent populations of redband trout (Oncorhynthus mykiss gairdneri) that had evolved in desert and montane climates." This was accomplished by rearing each pure strain and their F1 cross "in a common garden environment that they exposed over four weeks to diel water temperatures that were similar to those experienced in desert climates within the species' range," after which they state that "gill tissues were collected from the three strains of fish (desert, montane, F1 crosses) at the peak of heat stress and tested for mRNA expression differences across the transcriptome with RNA-seq."

This work revealed, as they succinctly describe it, that "redband trout from a desert climate have a much larger number of strongly differentially expressed genes than montane and F1 strains in response to heat stress, suggesting that a combination of genes has evolved for redband trout to adapt in their desert environment." And if redband trout can do it, many other species should also be able to "take the heat" of potential global warming and bask in its future progression ... that is, of course, if it ever begins to warm again.

References
Dahlhoff, E.P. and Rank, N.E. 2000. Functional and physiological consequences of genetic variation at phosphoglucose isomerase: Heat Shock protein expression is related to enzyme genotype in a montane beetle. Proceedings of the National Academy of Sciences 97: 10,056-10,061.

Hoffman, A.A., Sorensen, J.G. and Loeschcke, V. 2003. Adaptation of Drosophila to temperature extremes: bringing together quantitative and molecular approaches. Journal of Thermal Biology 28: 175-216.

Kavanagh, K.D., Haugen, T.O., Gregersen, F., Jernvall, J. and Vollestad, L.A. 2010. Contemporary temperature-driven divergence in a Nordic freshwater fish under conditions commonly thought to hinder adaptation. BMC Evolutionary Biology 10: 350.

Keller, I. and Seehausen, O. 2012. Thermal adaptation and ecological speciation. Molecular Ecology 21: 782-799.