Question: how to set Deseq factor
0
14 days ago by
fatimarasool13540 wrote:

Hi , I am new to R and this tool. i am following this given script

https://gist.github.com/stephenturner/f60c1934405c127f09a6

I want to do differential gene expression in my six samples. I want compare the expression of six samples .i have no control and exp data sample. i have simply six sample to compare to each other named as sample1. sample2, sample3, sample4, sample5 sample6..I have completed steps to stringtie now i want to use the Deseq tool . I have read tutorial. but i am stuck in this step how to set it according to my data

# Assign condition (first four are controls, second four contain the expansion)

(condition <- factor(c(rep("ctl", 4), rep("exp", 4))))

modified 14 days ago • written 14 days ago by fatimarasool13540

Actually i want this comparison `> combn(6,2)

`````` [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [,14] [,15]
``````

[1,] 1 1 1 1 1 2 2 2 2 3 3 3 4 4 5

[2,] 2 3 4 5 6 3 4 5 6 4 5 6 5 6 6`

1
14 days ago by
Haci120
Haci120 wrote:

If you check what the example code does, you will get your answer:

``````> factor(c(rep("ctl", 4), rep("exp", 4)))
[1] ctl ctl ctl ctl exp exp exp exp
Levels: ctl exp
``````

There are two levels, `ctl` and `exp`, and the code above is linking these levels with samples. Basically the first 4 samples are controls and the remaining are exp. This should be in the same order as your count table.

Your particular case, however, is not quite clear, the way you wrote your question implies that you do not have replicates, which I believe is not a good idea. Moreover, you want to compare all 6 samples with each other, which would provide 15 comparisons.

``````> combn(6,2)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [,14] [,15]
[1,]    1    1    1    1    1    2    2    2    2     3     3     3     4     4     5
[2,]    2    3    4    5    6    3    4    5    6     4     5     6     5     6     6
``````

If this is nevertheless what you want, just do:

``````> factor(1:6)
[1] 1 2 3 4 5 6
Levels: 1 2 3 4 5 6
``````

I also would like to point out that based on the tutorial you shared, you are using `Deseq2` and not `Deseq`, please see https://support.bioconductor.org/p/80395/

I have six RNAseq sample. ...how can i set the replicates ? Mean I havee to take the RNA from sample and sequenced it .?

I suggest you double check your experimental design, which hopefully includes biological replicates. Just declare the levels according to the order of the levels in the count matrix. For example if first three are control do the following:

``````> factor(c(rep("ctl", 3), rep("exp", 3)))
[1] ctl ctl ctl exp exp exp
Levels: ctl exp
``````

Or if every other sample is a control you can do this:

``````> factor(rep(c("ctl", "exp"), 3))
[1] ctl exp ctl exp ctl exp
Levels: ctl exp
``````

See the lines starting with `[1]`, they denote which sample is of what kind, control or treatment.

If you don't have any replicates and 6 levels, you should use this as can be seen in my initial answer:

``````> factor(1:6)
[1] 1 2 3 4 5 6
Levels: 1 2 3 4 5 6
``````

I am trying to create the coldata frame for DESeqDataSetFromMatrix design to instantiate the DESeqDataSet,

by using the following command

(coldata <- data.frame(row.names=colnames(countdata), condition))`

but i got this error

coldata <- data.frame(row.names=colnames(countData), condition)

Error in data.frame(row.names = colnames(countData), condition) :

row names supplied are of the wrong length

here is some lines of countDAta

``````> head(countData)

`G1 G2 G3  G4 G5 G6`
``````

`TraesCS3A02G388200 32 28 53 117 7 25

TraesCS1D02G394800 0 0 0 0 0 0

TraesCS6B02G054100 4 14 0 0 9 7

TraesCS6B02G127556 0 0 0 0 0 0

TraesCS6A02G372500 0 0 0 0 0 0

TraesCS2D02G097400 0 14 0 0 0 0`

enter code here

how can i resolve this error