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Phylotranscriptomic insights into the diversification of endothermic Thunnus tunas

Citation

Ciezarek, AG and Osborne, OG and Shipley, ON and Brooks, EJ and Tracey, SR and McAllister, JD and Gardner, LD and Sternberg, MJE and Block, B and Savolainen, V, Phylotranscriptomic insights into the diversification of endothermic Thunnus tunas, Molecular Biology and Evolution, 36, (1) pp. 84-96. ISSN 0737-4038 (2018) [Refereed Article]


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Copyright 2018 The Author(s). Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1093/molbev/msy198

Abstract

Birds, mammals, and certain fishes, including tunas, opahs and lamnid sharks, are endothermic, conserving internally generated, metabolic heat to maintain body or tissue temperatures above that of the environment. Bluefin tunas are commercially important fishes worldwide, and some populations are threatened. They are renowned for their endothermy, maintaining elevated temperatures of the oxidative locomotor muscle, viscera, brain and eyes, and occupying cold, productive high-latitude waters. Less cold-tolerant tunas, such as yellowfin tuna, by contrast, remain in warm-temperate to tropical waters year-round, reproducing more rapidly than most temperate bluefin tuna populations, providing resiliency in the face of large-scale industrial fisheries. Despite the importance of these traits to not only fisheries but also habitat utilization and responses to climate change, little is known of the genetic processes underlying the diversification of tunas. In collecting and analyzing sequence data across 29,556 genes, we found that parallel selection on standing genetic variation is associated with the evolution of endothermy in bluefin tunas. This includes two shared substitutions in genes encoding glycerol-3 phosphate dehydrogenase, an enzyme that contributes to thermogenesis in bumblebees and mammals, as well as four genes involved in the Krebs cycle, oxidative phosphorylation, β-oxidation, and superoxide removal. Using phylogenetic techniques, we further illustrate that the eight Thunnus species are genetically distinct, but found evidence of mitochondrial genome introgression across two species. Phylogeny-based metrics highlight conservation needs for some of these species.

Item Details

Item Type:Refereed Article
Keywords:endothermy, thermogenesis, phylogenomics, RNA-sequencing, transcriptomics, introgression, positive selection, mitochondrial–nuclear discordance
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Fish Physiology and Genetics
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Wild Caught
Objective Field:Wild Caught Fin Fish (excl. Tuna)
UTAS Author:Tracey, SR (Dr Sean Tracey)
UTAS Author:McAllister, JD (Mr Jaime McAllister)
ID Code:129895
Year Published:2018
Web of Science® Times Cited:168
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2018-12-20
Last Modified:2019-03-25
Downloads:6 View Download Statistics

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