Sequence alignment of mature miRNA sequences. The alignment was performed using the mature miRNA sequences of three Branchiostoma species (belcherii, bbe; floridae, bfl; japonicum, bj) and three vertebrates (Homo sapiens, has; Danio rerio, dre; Petromyzon marinus, pma). Different residues and insertions/deletions are highlighted in red in the alignment. The miR-9* sequence alignment showed several differences between Branchiostoma sp. a nd vertebrates. The sequences of mature miRNAs of B. floridae, Homo sapiens, Danio rerio, Petromyzon marinus were obtained from miRBase. The sequences of miRNAs of B. belcherii and B. japonicum from [12, 13].