design: After the genomic DNA of the sample is tested as qualified, the DNA is fragmented by mechanical interruption (ultrasound), and then the fragmented DNA is purified, repaired at the end, A is added at the 6 'end, and connected to the sequencing connector. Then, the agarose gel electrophoresis is used to select the size of the fragments, and PCR is expanded to form a sequencing library. The constructed library is first subject to library quality inspection, and the qualified library is sequenced.