Homology of bat miRNAs to vertebrate mature miRNAs in miRBase. P. alecto mature and star miRNAs were compared to a database of all vertebrate miRNAs extracted from miRBase (version 20) using BLASTN. 100% identity indicates that no internal gaps or mismatches were present in alignments between P. alecto miRNAs and their respective top BLAST hits. Minor length variations were allowed in this category, but the alignments were end-anchored to prevent mismatches at the termini. MiRNAs in the mismatch category had internal mismatches or indels relative to their top BLAST hits, whereas miRNAs in the no-hit category had no convincing BLAST hits. Search parameters are described in detail in the materials and methods.