Fig. 2

Correlation analysis of codon indices of chloroplast genes in Aroideae. A3s, T3s, G3s, C3s, composition at the third synonymous codon position; GC, overall GC content; GC3, GC content at the third position of the codons; GC12, average G/C contents of the 1st and 2nd positions of codons; CAI, codon adaptation index; CBI, codon bias index; FOP, optimal codon frequency; ENC, effective number of codons; Gravy, general average hydropathicity; Aromo, frequency of aromatic amino acids. *Significant at p < 0.05 (two-tailed); **Significant at p < 0.01 (two-tailed); ***Significant at p < 0.001 (two-tailed); ****Significant at p < 0.0001 (two-tailed) .