Figure 1

PCA score plots of the metabolites that showed significant abundance changes. For each dataset, PCA was performed on metabolites with statistically significant abundance changes (determined by corrected p-values) and the first (PC1) and second (PC2) principal components were plotted. The percentages indicate the amount of variation accounted for by each of these two components. The letters correspond to the TK stages at which the serum samples were taken from tadpoles as follows: A = TK VI–X, B = TK XII–XV, C = TK XVI–XVII, D = TK XVIII, E = TK XIX–XX, F = TK XXI–XXII, and G = > XXV. The score plots showed association between metabolite abundance change and the morphological measures (TK staging). (A) Tot⁺ dataset. (B) Tot^- dataset. (C) Aqu⁺ dataset. (D) Aqu^- dataset.