Tapestri libraries support two barcode structures based on chemistry type – V2 and V1. V1 is the older chemistry type, and V2 is the latest version. Runs for the two differ in manufacturing, biochemistry, panel content, and barcode structure. V1 chemistry is not manufactured anymore.
A barcode is a unique DNA sequence ligated to fragments within a sequencing library for downstream in-silico sorting and identification. The barcodes are attached to the 5' end of the R1 (forward) reads. After generating the DNA libraries, these barcodes need to be removed from the sequence and used as cell identifiers.
For more information, refer to the Tapestri Pipeline User Guide.
V2 Chemistry
Barcoding Bead: PhotoC-Element---Read 1 (36 bp)---BC1 (9 bp)---Off-Constant (14 – 17 bp)---BC2 (9 bp)---Constant2 (15 bp)
PhotoC-E is a linker that is bound between the Read 1 and the beads. This allows us to cleave the oligo from the beads when exposed to long-wave, low-wattage UV light.
Read 1 is the read primer where Illumina’s sequencing primer binds to start the sequencing process.
With Off-Constant offsets of 0 to 3 as follows:
- 0 Bases = no base
- 1 Base = C
- 2 Bases = TC
- 3 Bases = GTC
Forward Primer: Constant2 (15 bp)---Fwd primer (17 – 33 bp)
Reverse Primer: Rev primer (17 – 33 bp)---Read2 (34 bp)