UBC Research Data

Data from: Mechanisms of thermal adaptation and evolutionary potential of conspecific populations to changing environments Chen, Zhongqi; Farrell, Anthony P.; Matala, Amanda; Narum, Shawn R.

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Abstract
Heterogeneous and ever-changing thermal environments drive the evolution of populations and species, especially when extreme conditions increase selection pressure for traits influencing fitness. However, projections of biological diversity under scenarios of climate change rarely consider evolutionary adaptive potential of natural species. In this study, we tested for mechanistic evidence of evolutionary thermal adaptation among ecologically divergent redband trout populations (Oncorhynchus mykiss gairdneri) in cardiorespiratory function, cellular response and genomic variation. In a common garden environment, fish from an extreme desert climate had significantly higher critical thermal maximum (p3°C) than fish from cooler montane climate. In addition, the desert population had the highest maximum heart rate during warming (20% greater than montane populations), indicating improved capacity to deliver oxygen to internal tissues. In response to acute heat stress, distinct sets of cardiac genes were induced among ecotypes, which helps to explain the differences in cardiorespiratory function. Candidate genomic markers and genes underlying these physiological adaptations were also pinpointed, such as genes involved in stress response and metabolic activity (hsp40, ldh-b and camkk2). These markers were developed into a multi-variate model that not only accurately predicted critical thermal maxima, but also evolutionary limit of thermal adaptation in these specific redband trout populations relative to the expected limit for the species. This study demonstrates mechanisms and limitations of an aquatic species to evolve under changing environments that can be incorporated into advanced models to predict ecological consequences of climate change for natural organisms.; Usage notes
critical thermal maximumCTmax of three redband trout populations and a hybrid. Heating rate of water was 0.3°C min−1 to 22°C and 0.1°C min−1 thereafter until CTMAX was reached.maximum heart rateMaximum heart rate of three redband trout populations and a hybrid. Maximum heart rate was stimulated by an intraperitoneal injection of atropine sulfate and isoproterenol. Heating rate of water was 1 C every 6 minutes.metabolic rate and aerobic scopeStandard and maximum metabolic rate of three redband trout populations and a hybrid at 12°C, 15°C, 18°C, 21°C and 24°C. Maximum metabolic rate was achieved by exercise. Aerobic scope was calculated as the difference between standard and maximum rate.RAD TAG catelogRAD Tag sequence (75 bp ) and SNP position of the 5903 genetic markers.

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