What are R1, R2, R3, and I1 in a illumina sequencing data, and how can I get more information about them?

Question

[Vijith]

I am a fresher in Bioinformatics, especially in NGS. As of now, I am working on a WGS project, and the sequence read data include R1, R2, R3, and I1. I have understood that I1 is the index file, and based on query with someone I was told that R2 is barcode data. Can someone help me how we can delineate those information about the read files?

Answer 1

[GenoMax]

Are you sure this is a WGS project? In general these kind of data files are produced as a part of multiome 10x single-cell ATAC 10x projects produced by cellranger-arc mkfastq software. They are then used with cellranger-arc count.

I1: Dual index i7 read 
R1: Read 1
R2: Dual index i5 read
R3: Read 2 

Answer 2

[Prash]

I agree with GenoMax And even for natepairs, these are NOT the labeling used. I is certainly the index case. Can you please provide the screenshot of files?

[Vijith]

[Prash]

:-) I was expecting the file sizes. sorry