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Question: RNAseq DESeq2 paired data design help
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gravatar for umlch
4 months ago by
umlch0
umlch0 wrote:

Hello

I am conducting a DESeq2 analysis for differential gene expression using paired samples, featuring 2 drug treatments and 3 conditions. I have tried reading the vignettes and workflows but I am still a bit confused and would like a bit of confirmation from more advanced users. Here is my experiment design, including a column for nested individuals to achieve full rank.

individiual treatment phenotype ind.n
1 drug1 condition1 1
1 drug2 condition1 1
1 untreated condition1 1
2 drug1 condition1 2
2 drug2 condition1 2
2 untreated condition1 2
3 drug1 condition2 1
3 drug2 condition2 1
3 untreated condition2 1
4 drug1 control 1
4 drug2 control 1
4 untreated control 1
5 drug1 condition2 2
5 drug2 condition2 2
5 untreated condition2 2
6 drug1 control 2
6 drug2 control 2
6 untreated control 2
7 drug1 condition2 3
7 drug2 condition2 3
7 untreated condition2 3
8 drug1 condition2 4
8 drug2 condition2 4
8 untreated condition2 4
9 drug1 control 3
9 drug2 control 3
9 untreated control 3
10 drug1 condition1 3
10 drug2 condition1 3
10 untreated condition1 3
11 drug1 condition1 4
11 drug2 condition1 4
11 untreated condition1 4
12 drug1 control 4
12 drug2 control 4
12 untreated control 4

I have set up my dds design according to how the vignette seems to suggest and is as follows:

dds <- DESeqDataSetFromMatrix(countData = data,
                              colData = meta_data,
                              design = ~phenotype + phenotype:ind.n + phenotype:treatment)

which generates 

> resultsNames(dds)                      
 [1] "Intercept"                         "phenotype_Cond1_vs_Control"             "phenotype_Cond2_vs_Control"           
 [4] "phenotypeControl.ind.n2"               "phenotypeCond1.ind.n2"              "phenotypeCond2.ind.n2"            
 [7] "phenotypeControl.ind.n3"               "phenotypeCond1.ind.n3"              "phenotypeCond2.ind.n3"            
[10] "phenotypeControl.ind.n4"               "phenotypeCond1.ind.n4"              "phenotypeCond2.ind.n4"            
[13] "phenotypeControl.treatmentdrug1"   "phenotypeCond1.treatmentdrug1"  "phenotypeCond2.treatmentdrug1"

[16] "phenotypeControl.treatmentdrug2"    "phenotypeCond1.treatmentdrug2"   "phenotypeCond2.treatmentdrug2"

                         

I would like to ask the following questions from this dataset:

1)  Differentially expressed genes in response to treatments in each phenotype (i.e control (drug1 vs untreated), (drug2 vs untreated))

Is this information given by

res<- results(dds, name = "phenotypeControl.treatmentdrug1") Comparing (drug1 vs untreated) within control samples?

 

2) Then compare whether the treatment responses are different between phenotype (i.e. control (drug1 vs untreated) compared condition1 (drug1 vs untreated)

Is this generated by

res <- results(dds, contrast=list(c("phenotypeControl.treatmentdrug1,phenotypeCond1.treatmentdrug1")))?

 

3) and finally differentially expressed genes within treatment groups between phenotype (i.e Untreated (control vs condition1 vs condition2)

For this i believe I can't get this information with this setup? I tried keeping only the treatment data i'm looking at e.g. untreated to remove the variable and run a new analysis with 

dds <- DESeqDataSetFromMatrix(countData = data,
                              colData = meta_data,
                              design = ~phenotype)

 

I would be grateful if someone could give me some confirmation as to whether my process is correct or if not how to achieve what I need.

Thanks

ADD COMMENTlink modified 3 months ago by Michael Love19k • written 4 months ago by umlch0
0
gravatar for Michael Love
3 months ago by
Michael Love19k
United States
Michael Love19k wrote:

You've got the correct code for (1) and (2). For the third, can you say more? You want to test for any differences?

ADD COMMENTlink written 3 months ago by Michael Love19k
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