Table 3 Z-test of selection results for purifying selection (Ho: dn = ds, Ha: dn < ds) and positive selection (Ho: dn = ds, Ha: dn > ds) on alignments of (A) complete nad5 from 12 species with 543 positions, and (B)nad5 sequences corresponding to a putative translocated portion of nad5 from Anodonta cygnea (MF781083) from 12 species with 45 positions in the analysis. Alignments by ClustalW [36] and Z-tests were conducted in MEGA7 [37] using the Kumar method, 1000 bootstraps, and pairwise deletion. Statistically significant results are highlighted in bold using α = 0.05