Qualified DNA samples were randomly fragmented using a Covaris ultrasonicator.Large DNA fragments were enriched and purified via magnetic bead-based size selection.The fragmented DNA underwent damage repair and end-repair procedures.Stem-loop sequencing adapters were ligated to both ends of the DNA fragments, followed by exonuclease treatment to remove unligated fragments.The constructed libraries were sequenced on the PacBio Sequel IIe platform.