Paired-end tag

The main advantages of PET sequencing are its reduced cost by sequencing only short fragments, detection of structural variants in the genome, and increased specificity when aligning back to the genome compared to single tags, which involves only one end of the DNA fragment.

[1] Instead of cloning, adaptors containing the endonuclease sequence are ligated to the ends of fragmented genomic DNA or cDNA.

[1] Before sequencing, these PETs are ligated to adaptors to which PCR primers anneal for amplification.

The advantage of cloning based construction of the library is that it maintains the fragments or cDNA intact for future use.

Variations on library construction have been produced by next-generation sequencing companies to suit their respective technologies.

Workflow of Cloning and Cloning-free based PET library construction.
Example of PET detection of deletions and insertions.
Example of alternative transcript structures detected by RNA-PET.