Question: Is this procedure necessary in DESeq2 for my data
gravatar for michael.steffen
21 months ago by
michael.steffen20 wrote:

I want to make sure I am doing things correctly on DESeq2. 

Below is my design, it comprises 33 samples with 9 initial conditions. Associated with these conditions are some other factors such as age (old or young), further more, these 9 conditions can also be broken down into types (queen, foundress, guard, worker, and gyne).

I am interested in seeing pairwise differences between the 9 conditions, as well as the differences between age or state, however, I am unsure if I should take into account that extra information associated with the conditions (age, state. I thought I would have to, but based on the diversity of conditions, I am beginning to wonder if it is necessary or not. Could anyone let me know? Also, what would be the next step in accounting for everything in the design parameters themselves? 

expt_design <- data.frame(samples = colnames(total_counts), 
                          condition = c("AB", "AB", "AB", "FN", "FN", "FN", "FB", "FB", "FB", "GD", "GD", "GD", "GD", "FD", "FD", "FD", "FD", "FM", "FM", "FM", "FM", "FM", "GM", "GM", "GM", "GM", "GM", "MOM_MB", "MOM_MB", "MOM_MB", "D_MB", "D_MB", "D_MB"),
                          age       = c("old", "old", "old", "old", "old", "old", "old", "old", "old", "young", "young", "young", "young", "young", "young", "young", "young", "old", "old", "old", "old", "old", "old", "old", "old", "old", "old", "old", "old", "old", "young", "young", "young"))
                          type = c("queen", "queen", "queen", "foundress", "foundress", "foundress", "queen", "queen", "queen", "guard", "guard", "guard", "guard", "worker", "worker", "worker", "worker", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "queen", "gyne", "gyne", "gyne"))


dds <- DESeqDataSetFromMatrix( countData = total_counts, colData = expt_design, 
                               design = ~ condition + ? ? ? )  



ADD COMMENTlink modified 21 months ago • written 21 months ago by michael.steffen20

So I receive this error when doing ~age + type + condition.

Error in checkFullRank(modelMatrix) : 
  the model matrix is not full rank, so the model cannot be fit as specified.
  One or more variables or interaction terms in the design formula are linear
  combinations of the others and must be removed.

  Please read the vignette section 'Model matrix not full rank':


I think I understand the problem, and I think it is fundamental in my design. Can I not factor in age, or type, since they basically describe the condition as well? Can I only do contrasts between conditions, and combinations of conditions against each other? 


ADD REPLYlink written 21 months ago by michael.steffen20

I didn't compute the confounding in the design above, but yes, if the variables are confounded, you can only add in variables to the design which are "linearly independent". Basically this means, variables which separate the samples in other ways than the variables already in the design.

ADD REPLYlink written 21 months ago by Michael Love26k
Answer: Is this procedure necessary in DESeq2 for my data
gravatar for Michael Love
21 months ago by
Michael Love26k
United States
Michael Love26k wrote:

Check out this section:

You can have ~age + type + condition

And then use

results(dds, contrast=c("condition","FN","AB"))

etc to compare levels of any variable.

ADD COMMENTlink written 21 months ago by Michael Love26k
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