directional vs. non-directional sequencing

[frymor]

Hi,

Can someone please explain the difference between the directional and the non-directional sequencing methods?

I was looking for articles or sites which can explain it, especially the results one get from such run.

We have our results. This suppose to be a non-directional RNA-seq. The question was now, if we can extract the strand information from these data. I mean, is there a way to know if a strand belongs to the + or - strand?
In the bam file we have these results, but as far as I understand it, this information says only if the read was mapped to the forward or backward strand.

Am I wrong with this assumption?

I would appreciate ant information which will help me/us better understand the difference between the two technologies.

Thanks
A.

[henry.wood]

It's due to a difference in the library prep. Directional RNA-seq keeps the strand information by only making the cDNA in one direction, non-directional will make cDNA in both directions, so you have no way of knowing if your sequence read is in the same direction as the original transcription.