Mapping miRNA on miRBase

[nedoluzhko]

Hello, all! I have mapped my SOLiD reads on miRBase 19.0 (after trimming adapter, r/tRNA filtration and quality control) and found few animal and virus miRNA families in mine data. It is normal? One of these animal families is very dominant among all.

[nedoluzhko]

up this thread

[nedoluzhko]

UP. Any Answer?

[NicoBxl]

hey slow. let us time to answer.

So what are you type of library ? it's solid reads but did you use a special kit for small RNA ? whicj type of aligner did you use ? explain a little bit more of your workflow please.

[nedoluzhko]

Yes, I used SOLiD Total RNA Seq Kit (small RNA protocol), before I have conducted miRVanna enrichment. I am working with plant species without reference genom, unfortunately

Matching:


1. Preparation reads for analysis: Quality value control (SOLiD double-coded color reads with quality more than 15 were used); trimming of P2-adapter by Cutadapt program; filtration of ribosomal RNA using SILVA database and transfer RNA using Genomic tRNA database.
2. Bowtie 0.12.5 program. We mapped our 25 bp SOLiD reads on reference sequences from mirBase19.0. We used whole mirBase 19.0 for mapping with the allowance of 2-nt mismatch.
3. Generation of conservative miRNA list was conducted SAM files analysis script

[NicoBxl]

Did you try with an another alignment tool ? like blast ? bowtie is good to align small reads against a big reference sequence (like a genome) not small sequences.

And yes it can be normal to find some miRNA from other species. miRNA like mRNA are well conserved across species.

[nedoluzhko]

So, I will try! Many thanks for your help!

[vtosha]

Попробуйте для обработки miRDeep2, хорошая програмка. Ей можно скормить в качестве референсного любой близкий полный геном или даже просто имеющийся набор генов, она проведёт ряд фильтраций хитов по качеству и выдаст те микроРНК, что считает наиболее надёжными.

Try miRDeep2, software for searching miRNA in NGS reads. It can use as reference whole genome or set of genes, filtrate hits by quality and give out a most reliable miRNA.

[nedoluzhko]

Спасибо, Бласт, имхо, вообще не в тему.

Thank you!

[vtosha]

Если вопрос в том, может ли быть так, что среди растительных микроРНК встречаются животные, то, по-моему, может (http://www.plantcell.org/content/18/12/3355.short). Более свежих примеров навскидку не назову, но, кажется, такие есть.

If your first question was about if animal and viral microRNA was in your plant - it is possible (for example http://www.plantcell.org/content/18/12/3355.short).

[nedoluzhko]

Best! Thank you!

[vtosha]

I made a thread in Russian-language forum (http://molbiol.ru/forums/index.php?s...st=0&p=1348106) about microRNA, may be it will be useful for russian-speaking users.