Cold Fish

Arctic waters are home to a diverse group of fish that thrive in the cold, but is their cold-adaptation a result of similar genetic change across these distant taxa, or have they followed independent routes to polar adaptation? As the evolutionary change to the genome is the ultimate source of adaptation and loss, the lack of genomic resources for many Arctic fish has limited our ability to address such questions. Our newly developed transcriptomes for five phylogenetically distant fish commonly found in Arctic waters provides a new tool to begin addressing these questions. The proposed study would support the analysis of these transcriptomes, to identify genes that have come under changed selective pressure in the Arctic fish compared to closely related temperate and tropical species. This would allow the identification of biological systems that have been necessary for fish to succeed in the harsh Arctic environment, and to determine whether evolution in the cold has led to an accumulation of mutations in those systems responsible for dealing with heat. The latter is particularly important to investigate as the Arctic is warming at 2-3 times the global average, and if Arctic species have developed genomic lesions within their heat responding pathways then this may place those fish particularly at risk as water temperatures increase. Thus, analyzing the transcriptomes of these fishes offers a new view of their genetic 'gains' that allow them to thrive in the cold, and 'losses' that may now limit the ability of some to tolerate future warming. Further, as the targets of this study include important targets of subsistence fishing activity by native North Slope communities, building such understanding will have direct human impact.