highly significantp < 0.001
marginally significantp = 0.0580
Indeed, the two additional tryptophan residues lead to a significant difference in amino acid composition between the two putative ND6 variants (Wilcoxon test, p = 0.0181), which, in turn, explain the marginally significant difference in hydrophobicity (Wilcoxon test, p = 0.0580) and the highly significant differences in physicochemical features estimated by the Grantham [ 86 ] chemical distance (Wilcoxon test, p < 0.001) and the Schneider and Wrede [ 87 ] physicochemical distance (Wilcoxon test, p < 0.001).