The extracted gDNA was used for constructing BGISeq DNA PCR-free libraries. Libraries were constructed using the MGIEasy Universal DNA Library Prep Kit V1.0 (Cat. No.: 1000005250, MGI). The brief procedures are as follows: 1 g of genomic DNA was randomly fragmented using a Covaris instrument, and fragments with an average size of 200-400 bp were selected using MGIEasy DNA Clean Beads (Cat. No.: 1000005279, MGI). The selected fragments were subjected to end repair and 3' end adenylation, followed by adapter ligation. After PCR amplification of the DNA samples, the products were purified using MGIEasy DNA Clean Beads (Cat. No.: 1000005279, MGI). The double-stranded PCR products were thermally denatured and then circularized via splint oligonucleotide sequences in the MGIEasy Circularization Module (Cat. No.: 1000005260, MGI) to form single-stranded circular DNA (ssCir DNA) as the final library. Qualified libraries were sequenced on the DNBSEQ-T7RS platform.