Figure 2.

Scatterplots of the relationships in Exaiptasia pallida between mitochondrial genome copy number (mtDNA/nucDNA ratio) and (A) holobiont respiration rate normalized to host protein content (μmol O₂mg⁻¹ h⁻¹) and (B) host citrate synthase (CS) specific activity (U mg⁻¹). Closed symbols represent values obtained using the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene, while open symbols represent values obtained using the mitochondrial ATP-synthase subunit 6 (ATP6) gene. Copy numbers for both genes were normalized to that of eukaryotic translation elongation factor 1 alpha (EF-1-α), a single-copy nuclear gene in E. pallida. Neither of the relationships in (A,B) was statistically significant at p < 0.05. (C) Strong positive association between mtDNA/nucDNA as calculated using CO1 and ATP6 copy numbers normalized to EF-1-α.