Re: DiffBind time course

Rory Stark <[email protected]> Tue, 9 Sep 2014 13:43:54 +0000
Newsgroups gmane.science.biology.informatics.conductor
Message-ID <D034BF1B.49BA2%[email protected]>
Hello Enrico-

You can do some more advanced modelling using DiffBind, but to really get
the full power of the GLMs, you probably want to extract the binding
matrix and/or the edgeR/DESEq2 objects and run the appropriate RNA-seq
package directly.

Within DiffBind, you can use the "block" parameter in dba.contrast to
indicate the metadata field that has the timepoint. So if the
sample/control distinction is indicated as the Treatment and the timepoint
info is in the Condition, you can say:

> DBA = dba.contrast(DBA,categories=DBA_TREATMENT, block=DBA_CONDITION)
> DBA = dba.analyze(DBA) # for default edgeR analysis

This will model the data as [~Condition + Treatment] and give you the
effects of the treatment consistent across timepoints. There are other
models you may want to fit, (eg [~Condition * Treatment]); for this you
would need to run edgeR (or DESeq/DESeq2) independently -- their
respective vignettes give examples of analyzing time series data.

-Rory

On 09/08/2014 12:02, Enrico Ferrero <[email protected]>  wrote:

>
>----------------------------------------------------------------------
>
>Message: 1
>Date: Mon, 8 Sep 2014 12:01:57 +0100
>From: Enrico Ferrero <[email protected]>
>To: "[email protected]" <[email protected]>
>Subject: [BioC] DiffBind time course
>Message-ID:
>	<CAO22HXcAQM_61p7uH4KSKkM13yFn5G5hp7fZS32+cBGTNnpzDw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
>Content-Type: text/plain; charset=UTF-8
>
>Hi,
>
>Is there a way to use DiffBind to analyse time course data?
>I have sample and control replicates at five different time points and
>I would like to know which sites show differential binding over time.
>
>At the moment I'm doing multiple pairwise comparisons (i.e: sample at
>24h vs control at 24h) and I'm trying to understand if it's possible
>at all and, if yes, what parameters I should pass to dba.contrast()
>and dba.analyze().
>
>Thanks!
>
>-- 
>Enrico Ferrero

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