Question: Can I change the sequencing read lengths of the i5 and i7 indices?
Answer: Chromium Single Cell 3' Gene Expression v3.1 Dual Index libraries and Visium Spatial Gene Expression libraries are dual index libraries.
The i5 and i7 reads are necessary to identify the Sample Indexes. These Sample Indexes are needed to distinguish between pooled libraries and are used for demultiplexing. If the i5 and i7 reads are shortened, it may be difficult to demultiplex pooled samples. If only one sample is being sequenced in one lane, the impact of shorter i5 or i7 reads may be diminished.
It is best practice to adhere to the recommended sequencing lengths.
Product: Visium, Single Cell Gene Expression