design: 1.High quality genomic DNA was extracted and tested for purity, concentration and integrity by Nanodrop, Qubit and 0.35% agarose gel electrophoresis; 2. Recovery of large fragments of DNA;3. Library construction :(1)DNA damage repair and terminal repair, magnetic bead purification;(2) joint connection, magnetic beads purification;(3)Qubit library quantification;4. Sequencing on the machine.