cpg.annotate model requirements
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kadm • 0
@kadm-21455
Last seen 21 months ago

I am using ChAMP to process EPIC methylation array data. While delving into the source code for champ.DMR for another reason, I noticed that it defined the linear model used in the DMRcate method as ~ pheno. Further delving revealed that champ.DMR calls DMRcate::cpg.annotate, which itself requires a model with an intercept (e.g. it is has this in the function stopifnot(colnames(design)[1] == "(Intercept)")).

Is there any way to circumvent this and input a model into DMRcate (and thus, into champ.DMR) that has no intercept, as in 0 + pheno? This is necessary as other methods (like champ.DMP) already use a no intercept model.

DMRcate ChAMP • 258 views
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You can specify contrasts=TRUE and pass a contrasts matrix (as you would in limma) to cpg.annotate; this will allow you to fit non-intercept models.

Tim

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Yuan Tian ▴ 220
@yuan-tian-13904
Last seen 11 weeks ago
University College London

Hi, Kadm:

Sorry that ChAMP did not designed parameter to set intercept in DMRcate, thus I suggest you directly run DMRcate package with specific settings. The result should not be too hard to organize.

Best Yuan Tian

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