How does next-generation sequencing (NGS) work?

The first step in next-generation sequencing is the preparation of an NGS library, in which DNA is fragmented and sized based on the optimal insert size, which depends on the sequencing application used. Adapters are then attached to both ends of each fragments and then the library is amplified using PCR, after which the product can then be sequenced using one of many platforms, such as Ion Torrent or Illumina’s MiSeq.