Illumina NextSeq 500 Read Length

Question

[analyst]

Hi scientists,

I have downloaded secondary dataset from NCBI GEO Dataset sequenced through Illumina NextSeq 500. QC report of the data tells that read length ranges between 10-76. Is it normal?

[jv]

10 bases is pretty short for sequencing data, depending on the type of data and your goals you might benefit from additionally filtering for a min read length if you plan to use this data

[analyst]

Thanks jv!

My goal is to perform differential gene expression analysis. What should be the minimum read length?

[jv]

check out https://www.biostars.org/p/401642/#401642

Answer 1

[GenoMax]

QC report of the data tells that read length ranges between 10-76. Is it normal?

If the data is pre-trimmed then yes this can be expected. If you know that the data is not trimmed then every read should be the same lenght (max number of cycles sequenced).

[analyst]

Thanks GenoMax! Its raw data collected from GEO Datasets (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE221295).