design: First of all, the original samples were extracted for DNA, and then the quality of the DNA samples was checked. Two methods were used to detect the DNA: (1) Agarose gel electrophoresis was used to analyze the degree of DNA degradation and whether the DNA was contaminated by RNA and protein. (2) Qubit accurately quantifies DNA concentration. (3) The genomic DNA was fragmented by 26GNeedle, and the fragments more than 20kb were selected by BluePippin. After end repair and A-tail addition, the two ends of the fragments were connected with connectors to prepare DNA library. (4) After the constructed library was quantified by Qubit concentration and qualified by quality inspection, the Nanopore platform was used for sequencing according to the effective concentration of the library and the demand for data output.