[BioC] No replicates and differential analysis !!

[Sean Davis]

On 1/25/06 9:19 AM, "Nicolas Servant" <Nicolas.Servant at curie.fr> wrote:

> Thanks for your answer,
> But in this case, i have to choose a fold change threshold ! And it is
> supported that the FC tends to be greater at low expression levels.
> For instance a FC greater than 2 for expression values near 50 is
> readily seen, but it is low probability to observe FC greater than 2 for
> expression values near 1000
> So i would like to use a more robust approach.

Unfortunately, I don't think there is a truly more robust approach with only
one measurement (the ratio) for each gene.  The answer here is to do more
replicates or to take your gene list as a source of "candidates" that you
then validate using another technology (PCR, for example).  If you really
need to assign some statistical significance (rather than just ranking genes
for further analysis), then I think you have no choice but to do further
arrays.

Sean