Table 1.

Candidate Genes Underlying the Evolution of Endothermy in Bluefin Tunas (see text for details).

Gene Name	Gene Abbreviation	Uniprot Reference Sequence and Site of Mutation	Consurf Amino Acid Site Phylogenetic Conservation Score (1 = highly variable, 9 = highly conserved)	Change in Protein Stability (pseudofolding-free energy ΔΔG)	Significant Change in Electrostatic Potential? (nonparametric Wilcoxon signed-rank test)	Putative Function
Glycerol-3-phosphate dehydrogenase 1b	GPD1b	F1QGK0_DANRE: 219	3	−0.8	Increase (Z-score 3.37)	Transfers cytosolic NADH, produced by glycolysis, to mitochondrial glycerol-3-phosphate dehydrogenase as NAD+, which then feeds oxidative phosphorylation (McDonald et al. 2017)
Glycerol-3-phosphate dehydrogenase 1c	GPD1c	Q7T3H5_DANRE: 278	6	−0.9	No (Z-score 1.6)	As with GPD1b
Aconitase 2	ACO2	F8W4M7_DANRE: 452	2	−0.3	Decrease (Z-score −2.1)	Mitochondrial aconitase isoform. Controls cellular ATP production by regulating intermediate flux in the Krebs cycle (Lushchak et al. 2014)
ATP synthase, H+ transporting, mitochondrial F1 complex, gamma polypeptide 1	ATP5C1	Q6P959_DANRE: 198	4	−2.1	No (Z-score 0.8)	Encodes gamma subunit of mitochondrial ATP synthase. This catalyzes ATP synthesis during oxidative phosphorylation (Matsuda et al. 1993)
Hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), beta subunit	HADHB	Q7ZTH6_DANRE: 189	1	−0.6	Decrease (Z-score −5.1)	Subunit of mitochondrial trifunctional protein, which catalyzes the last three steps of mitochondrial β-oxidation of long-chain fatty acids. This in turn feeds the krebs cycle and aerobic metabolism (Naiki et al. 2014)
Superoxide dismutase 1, soluble	SOD1	SODC_DANRE: 92 and 93	Site 92: 1 Site 93: 2	Site 92: +0.4 Site 93: −1.1	Site 92: No (Z-score 0.7) Site 93: Increase (Z-score 4.4)	Destroys toxic free radicals, the majority of which are produced by mitochondria (Mattiazzi et al. 2002)

Note.—Amino acid changes are provided in figure 1.