title: The metagenome of consortium HL
design: Carry out end flattening repair on that interrupt DNA, adding a base' a' at the 3' end to convert into a sticky end, and adding a DNA linker comprise an Index sequence at two sides of the sticky end through base complementation. The target fragments within a certain length range were collected by magnetic bead screening, and Index was added at the end of the target fragment by PCR amplification to complete the construction and detection of the sequencing library. The sequencing library was combined onto the sequencing chips by bridge PCR, and finally sequenced using Illumina HiSeq or MiSeq according to the fragment size.