design: PCR products (400-450bp) amplifying junctions of sequence adaptors and either HBV 5 end or 3 end  were subjected to DNA sequencing library preparation.  The aimed insert size of 300-350bp was achieved by Covaris M220 sonication. Tecan Celero DNA-Seq kit (Tecan, Cat#0360A-UDI) was used to produce the final library with unique dual-indexes.