Phylogenetic tree based on the alignment phage int ORFs. The amino acid sequence of φRSA1 ORF50 is compared with int sequences of Bm23344 (accession no. Q62FM0), φ52237 (accession no. Q45Y16), DaRCB (accession no. Q47H88), Sf8401 (accession no. Q0T7U1), P2 (accession no. P36932), φRSX (accession no. Q8Y3C8), and φCTX (accession no. Q38644). The analysis was performed by the multiple-alignment program CLUSTAL W.