Hello,

I'm trying to get my head around some DESeq2 results and I would really appreciate some help.

I have two conditions (control and disease) and one continuous variable (age). Each of the conditions would be conformed by 100 individuals with different ages. I want to see which changes occur in the control group as age increases, and the same thing with the disease group (I know this would be optimally with the same individuals in different time points but I'm working with post-mortem tissue so this is the best i can do).

I have set my DESeq2 design as ~condition+age+condition:age

From resultsNames(dds) I get:

  [1]  "Intercept" "condition_disease_vs_ctrl" "age" "conditiondisease.age"

I suppose that "conditiondisease.age" is the name I am interested for the disease group. But is "age" the one for the control? (since it is the reference level) Or is it age regardless of the condition? (if it is this option, how can i get "conditionctrl.age"?)

I also have a question on how to interpret the log2FC on this, according to the vignette this would be the change per unit of the continuous variable (age). If age is integers, is this set to have the lowest value (youngest in my setup) as a reference point? Or the highest (oldest)?

And one more, do I have to sort age before giving it to DESeq2? I am guessing no but it doesn't hurt to ask.

Thank you!!