I have an animal experiment with 4 different groups:
A) control diet + vehicle
B) control diet + drug
C) experimental diet + vehicle
D) experimental diet + drug.
We then measure the expression of several genes.
The specific question that we want to ask is:
Does the dietary intervention affect gene expression independently of the drug?
Therefore I performed a two way anova (usign graphpad prism) and the results table states that there is no significant interation (P=0.5), there is a significant effect of the diet (p=0.027) and no effect of the drug (p=0.4398)
When I then perform a tukey comparison of all the values, there are no statistical significances in any of the groups.
I also did a statistical comparison of just the row factor (diet) with a
Sidak post-hoc test and again, there is no significant difference.
How would you then intrepert this data for publication purposes? On one hand, the anova tells us that a significant portion of the deviance in the groups comes from the diet, but without differences in any post-hoc test, I do not know how to write this up.
Thanks in advance to anyone that can help!