Hi everyone,
I have six libraries of small RNA sequences from illumina platform, among them 5 show normal length distribution (24nt sRNAs are the most abundant followed by 21, 22, and 23nt sRNAs, while the rest very short (17-20nt) and longer ones (25-28nt) are of low abundance) after mapping to reference genome sequences and removing rRNA, tRNA, snoRNA, and snRNA sequences. But one library show abnormal length distribution, with 17nt sRNAs as the most abundant ones and less and less abundant as their length increase. Has anyone ever seen such length distribution for sRNAs? If I still want to use this library for differential expression especially miRNAs, dose anyone have any idea of how to normalize the data?
Length distribution of the one sRNA library attached below
I have six libraries of small RNA sequences from illumina platform, among them 5 show normal length distribution (24nt sRNAs are the most abundant followed by 21, 22, and 23nt sRNAs, while the rest very short (17-20nt) and longer ones (25-28nt) are of low abundance) after mapping to reference genome sequences and removing rRNA, tRNA, snoRNA, and snRNA sequences. But one library show abnormal length distribution, with 17nt sRNAs as the most abundant ones and less and less abundant as their length increase. Has anyone ever seen such length distribution for sRNAs? If I still want to use this library for differential expression especially miRNAs, dose anyone have any idea of how to normalize the data?
Length distribution of the one sRNA library attached below