The following is the procedure on how a DNA fragment over 6kb is sequenced:
1) Digest DNA with physical reactions.
2) Recover pieces with 1-1.5K fragments.
3) Use nuclease to cut the end, conjugated into the carrier.
4) Since fragments will overlap with each other, we ensure that each section to be read at least three times.
5) Combine all sequencing data together.
6) If there is missed regions, further sequencing steps is needed to complete the sequence.