Velvet/Oases transcript expression level?

[[email protected]]

Hi,
I am in the process of de novo transcriptome assembly from a non-model eukaryote. I have 17 million 65 bp, paired-end reads that I have assembled with Velvet and then Oases. This gives nice results in that I am getting full-length contigs that appear reasonable when compared to orthologues in related model eukaryotes. However, I am really after relative transcript expression levels. Does anyone know if there as a way that I can get information on that from this software combination?

[konrad98]

Hi Simon,

I'm not by any means an expert on this, but you probably have two options:

1. Convert the kmer coverage in the stats.txt file to base-coverage and use that as a proxy for expression level

2. Align the reads to the assembled transcripts using something like Bowtie and then extract the coverage of each transcript using SAMTools

Hope that helps!

[choy]

Velvet question

How can one extract all of the reads that were used in the assembly, in order to do the re-mapping step you described?

[konrad98]

Under the contrib/extractContigReads directory in Velvet you'll find a script to do this